move exercises, lecture examples, labs into subfolders

Exercises/C10/ex2.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <math.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+int main() {
+	float input, output;
+	printf("Enter an angle in degrees: ");
+	scanf("%f", &input);
+
+	output = degrees_to_radians(input);
+
+	printf("%f radians\n", output);
+
+	return 0;
+}

Exercises/C10/ex3.c

@@ -0,0 +1,36 @@
+#include <stdio.h>
+#include <math.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+
+int main() {
+	int rc, start, end;
+
+	printf("Start: ");
+	rc = scanf("%d", &start);
+	if (rc != 1) {
+		printf("Please enter a real integer\n");
+		return 1;
+	}
+	printf("End: ");
+	rc = scanf("%d", &end);
+	if (rc != 1) {
+		printf("Please enter a real integer\n");
+		return 1;
+	}
+
+	if (start > end) {
+		printf("Please ensure that start value is smaller than end value\n");
+		return 1;
+	}
+
+	for (int i = start; i <= end; i++) {
+		printf("%d %f\n", i, degrees_to_radians((float)i));
+	}
+
+	return 0;
+}

Exercises/C10/ex4.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+
+int date_to_day(int year, int month, int day) {
+	if (month < 3) {
+		month += 12;
+		year -= 1;
+	}
+
+	return ((13*month+3)/5 + day + year + year/4 - year/100 + year/400) % 7;
+}
+
+int main() {
+	int rc, year, month, day, nd;
+
+	printf("Enter a day (yyyy-mm-dd): ");
+	rc = scanf("%d-%d-%d", &year, &month, &day);
+	if (rc != 3) {
+		printf("Failed to parse date\n");
+		return 1;
+	}
+
+	nd = date_to_day(year, month, day);
+
+	switch (nd) {
+		case 0:
+			printf("Monday\n"); break;
+		case 1:
+			printf("Tuesday\n"); break;
+		case 2:
+			printf("Wednesday\n"); break;
+		case 3:
+			printf("Thursday\n"); break;
+		case 4:
+			printf("Friday\n"); break;
+		case 5:
+			printf("Saturday\n"); break;
+		case 6:
+			printf("Sunday\n"); break;
+	}
+
+	return 0;
+}

Exercises/C10/ex5.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+
+int date_to_day(int year, int month, int day) {
+	if (month < 3) {
+		month += 12;
+		year -= 1;
+	}
+
+	return ((13*month+3)/5 + day + year + year/4 - year/100 + year/400) % 7;
+}
+
+void print_day_of_week(int day) {
+	switch (day) {
+		case 0:
+			printf("Monday\n"); break;
+		case 1:
+			printf("Tuesday\n"); break;
+		case 2:
+			printf("Wednesday\n"); break;
+		case 3:
+			printf("Thursday\n"); break;
+		case 4:
+			printf("Friday\n"); break;
+		case 5:
+			printf("Saturday\n"); break;
+		case 6:
+			printf("Sunday\n"); break;
+	}
+}
+
+int main() {
+	int rc, year, month, day, nd;
+
+	printf("Enter a day (yyyy-mm-dd): ");
+	rc = scanf("%d-%d-%d", &year, &month, &day);
+	if (rc != 3) {
+		printf("Failed to parse date\n");
+		return 1;
+	}
+
+	nd = date_to_day(year, month, day);
+	print_day_of_week(nd);
+
+	return 0;
+}

Exercises/C10/function_example.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+// Define HOW the function is to be used, code comes later
+float CalculateSurfaceAreaOfCylinder ( float R, float L );
+
+// Function to calculate the volume of a cylinder
+float CalculateVolumneOfCylinder ( float R, float L )
+{
+	// Calculate  \& return value
+	float Result;
+	Result = (M_PI * R * R * L);
+	return (Result);
+}
+int main(void)
+{
+    // Declare variables
+    float r, l, SurfaceArea, Volume;
+
+    // Obtain values
+    printf("\nPlease enter the radius");
+    scanf("%f", &r);
+
+    printf("\nPlease enter the length");
+    scanf("%f", &l);
+
+    // Get and display the volume
+    Volume = CalculateVolumneOfCylinder(r, l);
+    printf ("\nThe volume is %f", Volume);
+
+    // Get and display the surface area
+    SurfaceArea = CalculateSurfaceAreaOfCylinder(r, l);
+    printf ("\nThe surface area is %f", SurfaceArea);
+
+    return 0;
+}
+// Calculate the surface areas of a cylinder
+float CalculateSurfaceAreaOfCylinder ( float R, float L )
+{
+	// Calculate  \& return value
+	return (2 * M_PI * R * R ) +  ( 2 * M_PI * R * L);
+}

Exercises/C10/void_function_example.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Define HOW the function is to be used, code comes later
+void DisplayDayOfTheWeek ( int Day );
+
+int main(void)		// Execution starts here
+{
+   	int d;	// Declare variable
+
+    // Obtain values
+    printf("\nPlease enter a number betwwen 0 and 6");
+    scanf("%d", &d);
+
+    // Use a function to display the day of the week
+    DisplayDayOfTheWeek(d);
+
+    return 0;
+}
+
+// Function to display day of week - nothing is returned
+void DisplayDayOfTheWeek ( int Day )
+{
+    // Display date based on value
+    // Case values on one line as easier to cut/paste :-)    
+    switch (Day)
+    {
+			case 0 : printf ("Sunday") ; break;
+			case 1 : printf ("Monday") ; break;
+			case 2 : printf ("Tuesday") ; break;
+         
+		    /* etc. for other days of the week */    
+    
+    	default:
+        	printf ("Invaid day provided");
+    }
+    return;	// No value needed as the return type is void
+}

Exercises/C11/array_loop_example_1.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) // Main : Execution starts here...
+{
+    // Declare variables - pre-populate the array
+    int Ages[10] = {12,34,23,11,8,19,6,44,9,16};
+    int i;
+
+    // Loop from 0 to 9 inclusive
+    for  ( i = 0 ; i < 10 ; i++ )
+        printf ("Item %d contains value %d\n",i ,Ages[i]);
+
+    // Exit the application
+    return 0;
+}

Exercises/C11/array_loop_example_2.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main () - execution starts here
+int main (void)
+{
+    // Declare variables
+    int SampleData[10];
+    int a=0;
+
+    // Show initial value of a
+    printf ("Values in a is %d \n", a);
+
+    // Change an array item that IS NOT DEFINED
+    SampleData[10] = 20;
+
+
+    // See how thi affect the value in a
+    printf ("Values in a is %d \n", a);
+
+    // Note: we can retieive this 'invalid' value - it is however 'a' we are getting
+    printf ("Values in SampleData[10] is %d \n", SampleData[10]);
+
+    return (0);     // Exit indicating sucess
+}

Exercises/C11/ex2.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+#define ARRAY_LEN 90
+
+int main() {
+	int i;
+	float arr[ARRAY_LEN];
+
+	for (i = 0; i < ARRAY_LEN; i++) {
+		arr[i] = (float)i;
+	}
+	for (i = 0; i < ARRAY_LEN; i++) {
+		printf("%d %f\n", i, arr[i]);
+	}
+}

Exercises/C11/ex3.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <math.h>
+
+#define ARRAY_LEN 90
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+int main() {
+	int i;
+	float arr[ARRAY_LEN];
+
+	for (i = 0; i < ARRAY_LEN; i++) {
+		arr[i] = degrees_to_radians((float)i);
+	}
+
+	for (i = 0; i < ARRAY_LEN; i++) {
+		printf("%d %f\n", i, arr[i]);
+	}
+}

Exercises/C11/initialise_string_example_1.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main : Execution starts here...
+int main(void)
+{
+	// Declare variable - pre-populate the array
+	char msg[] = {'H','i',' ','W','o','r','l','d','\0'};
+
+	// Output with printf
+	printf ("The text is: %s\n", msg);
+
+	puts(msg); // We could also use puts to display the string
+
+	return 0;    // Exit the application
+}

Exercises/C11/initialise_string_example_2.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) // Main : Execution starts here...
+{
+	// Declare variable - pre-populate the array
+	char msg[] = "Hello World";
+
+	// Output with printf
+	printf ("The text is: %s\n", msg);
+
+	puts(msg); // We could also use puts to display the string
+
+	return 0;      // Exit the application
+}

Exercises/C12/scope_of_variables.c

@@ -0,0 +1,20 @@
+void SampleFunction1 ( int x )
+{	
+	int i,j,k;
+	return;
+}
+
+void SampleFunction2 ( int x )
+{
+	int i,j,k;
+	SampleFunction1(x);
+	return;
+}
+
+// Main : Execution starts here...
+int main(void)
+{
+	int i = 1;
+	SampleFunction2(i);
+	return 0;
+}

Exercises/C13/AccessingViaPointers/accessing_via_pointers.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main (void )
+{
+    // Declare a in integer
+    int c,d;
+
+	// Declar and integer pointer
+	int *ptrC;
+
+	// Some assgnments
+    c = 10; // C now contains the value 10
+    ptrC = &c;   // ptrC now 'Points' to c
+
+    // Get the value of c via the pointer and store in d
+    d = *ptrC;  // d now contains 10
+    printf ("\nThe value in d is %d", d);
+
+    // Change the value of c via the pointer ptrC
+    *ptrC = 1;  //c now contains 1
+    printf ("\nThe value in c is %d", c);
+
+	return 0;   // exit
+}

Exercises/C13/assigning_pointers.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main (void )
+{
+    // Integer variables
+    int a, ValueB, d;
+
+	// integer pointers
+	int *ptrA=&a, *B=&ValueB, *Data=&d;
+
+	// Float variables
+	float f,y,z;
+
+	// Float pointers
+	float *pf=&f , *q=&y, *Zvalue=&z;
+
+	// We could also do this on separate lines e.g.
+	int SomeData;
+	int *Another;
+	Another = &SomeData;
+
+	return 0;
+}

Exercises/C13/ex2.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main (void )
+{
+	// Declare a in integer
+	int c,d;
+
+	// Declar and integer pointer
+	int *ptrC;
+
+	// Some assgnments
+	c = 10; // C now contains the value 10
+	ptrC = &c;   // ptrC now 'Points' to c
+
+	*ptrC = 20;
+
+	// Get the value of c via the pointer and store in d
+	d = *ptrC;  // d now contains 10
+	printf ("The value in d is %d\n", d);
+
+	// Change the value of c via the pointer ptrC
+	*ptrC = 1;  //c now contains 1
+	printf ("The value in c is %d\n", c);
+
+	return 0;   // exit
+}

Exercises/C13/ex3.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main (void )
+{
+	// Declare a in integer
+	float c,d;
+
+	// Declar and integer pointer
+	float *ptrC;
+
+	// Some assgnments
+	c = 10; // C now contains the value 10
+	ptrC = &c;   // ptrC now 'Points' to c
+
+	*ptrC = 20;
+
+	// Get the value of c via the pointer and store in d
+	d = *ptrC;  // d now contains 10
+	printf ("The value in d is %f\n", d);
+
+	// Change the value of c via the pointer ptrC
+	*ptrC = 1;  //c now contains 1
+	printf ("The value in c is %f\n", c);
+
+	return 0;   // exit
+}

Exercises/C14/Makefile

@@ -0,0 +1 @@
+include ../../Makefile

Exercises/C14/ex1.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <math.h>
+
+void cartesian_to_polar(float x, float y, float *r, float *theta) {
+	*r = sqrtf(x*x + y*y);
+	*theta = y/x;
+}
+
+int main() {
+	int rc;
+	float x, y, r, theta;
+
+	printf("x: ");
+	rc = scanf("%f", &x);
+	// check that scanf was successful by checking if it returned 1 (1 successfully scanned item)
+	if (rc != 1) {
+		printf("Please enter a real number\n");
+		return 1;
+	}
+
+	printf("y: ");
+	rc = scanf("%f", &y);
+	if (rc != 1) {
+		printf("Please enter a real number\n");
+		return 1;
+	}
+
+	cartesian_to_polar(x, y, &r, &theta);
+	printf("r=%f theta=%f\n", r, theta);
+
+	return 0;
+}

Exercises/C14/ex2.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <math.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+void process(float degrees, float* radians, float* sin_val, float* cos_val, float* tan_val) {
+	*radians = degrees_to_radians(degrees);
+	*sin_val = sin(*radians);
+	*cos_val = cos(*radians);
+	*tan_val = tan(*radians);
+}
+
+
+int main() {
+	float degrees, radians, sin_val, cos_val, tan_val;
+
+	printf("Degrees: ");
+	scanf("%f", &degrees);
+
+	process(degrees, &radians, &sin_val, &cos_val, &tan_val);
+
+	printf("Radians: %f\n", radians);
+	printf("Sine: %f\n", sin_val);
+	printf("Cosine: %f\n", cos_val);
+	printf("Tangent: %f\n", tan_val);
+}

Exercises/C14/ex3.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <math.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+void process(float degrees, float* radians, float* sin_val, float* cos_val, float* tan_val) {
+	*radians = degrees_to_radians(degrees);
+	*sin_val = sin(*radians);
+	*cos_val = cos(*radians);
+	*tan_val = tan(*radians);
+}
+
+
+int main() {
+	int degrees_start, degrees_end;
+	float radians, sin_val, cos_val, tan_val;
+
+	printf("Start: ");
+	scanf("%d", &degrees_start);
+	printf("End: ");
+	scanf("%d", &degrees_end);
+	printf("Degs\tRad\tsin\tcos\ttan\n");
+
+	for (int i = degrees_start; i <= degrees_end; i++) {
+		process((float)i, &radians, &sin_val, &cos_val, &tan_val);
+		printf("%d\t%0.3f\t%0.3f\t%0.3f\t%0.3f\n", i, radians, sin_val, cos_val, tan_val);
+	}
+
+
+}

Exercises/C14/quadratic_solver.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+int SolveQuadraticEquation(float a, float b, float c, float *x1, float *x2)
+{
+    float d;    // For storing b^2 - 4*a*c
+
+    if ( a == 0)    // Not a quadratie
+    {
+        return -1;
+    }
+
+    // calculate and store b*b-4*a*c for testing ans use later (if OK)
+    d = b*b - 4*a*c;
+
+    if ( d < 0 )
+    {
+        return -1;  // Complex
+    }
+
+    // If we have got to here, we can calculate x1 and x2
+    *x1 = ( -b + sqrt (d)) / (2 * a);  // Note the use of the * before x1 & x2
+    *x2 = ( -b - sqrt (d)) / (2 * a);  // to write to the relevant memory locations 
+
+    // As we got here OK, return 0 to indicate all is OK
+    return 0;
+}
+
+int main (void ) 
+{
+    float A,B,C,x1,x2;
+    int retval;
+
+    printf ("Please enter coefficients A,B and C separated by a space\n");
+    scanf ("%f %f %f", &A, &B, &C);
+
+    // Make use of the function
+    retval = SolveQuadraticEquation(A, B, C, &x1, &x2);
+
+    // Use the retval to determine if we can display the answers or an derror message
+    if ( retval == -1 )
+    {
+        printf ("Not a quadratic\n");
+    }
+    else if (retval == -1)
+    {
+        printf ("The solution is complex - I cannot solve these\n");
+    }
+    else
+    {
+        printf("\nThe solutions are x1=%f, x2=%f", x1, x2);
+    }
+    return 0;   // exit
+}

Exercises/C14/quadratic_solver_function.c

@@ -0,0 +1,24 @@
+int SolveQuadraticEquation(float a, float b, float c, float *x1, float *x2)
+{
+    float d;    // For storing b^2 - 4*a*c
+
+    if ( a == 0)    // Not a quadratie
+    {
+        return -1;
+    }
+
+    // calculate and store b*b-4*a*c for testing ans use later (if OK)
+    d = b*b - 4*a*c;
+
+    if ( d < 0 )
+    {
+        return -1;  // Complex
+    }
+
+    // If we have got to here, we can calculate x1 and x2
+    *x1 = ( -b + sqrt (d)) / (2 * a);  // Note the use of the * before x1 & x2
+    *x2 = ( -b - sqrt (d)) / (2 * a);  // to write to the relevant memory locations
+
+    // As we got here OK, return 0 to indicate all is OK
+    return 0;
+}

Exercises/C15/pointer_array_example_1.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare and populate an integer array
+    int MyArray[10] = {2,4,6,8,10,12,14,18,20};
+    
+    // Declate an integer pointer
+    int *pI;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];
+
+    // Or, use the fact the array name on its own is the start address of the array
+    pI = MyArray;
+
+    return 0;   // Exit
+}

Exercises/C15/pointer_array_example_2.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare an integer array and an integer pointer
+    int MyArray[10] = {2,4,6,8,10,12,14,16,18,20};
+    int *pI;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];   // Or use:     pI = MyArray;
+
+    // Display the 1st item in the array, first be accessing rhe array
+    printf("The value at array item [0] is %d\n", MyArray[0]);
+
+    // Since the pointer points to the address of the 1st item we can
+    // access it as we would for a pointer pointing to any single variable
+    
+    printf("The value at the memory address held in pI is %d\n", *pI);
+
+    return 0;   // Exit
+}

Exercises/C15/pointer_array_example_3.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare an integer array and an integer pointer
+    int MyArray[10] = {2,4,6,8,10,12,14,16,18,20};
+    int *pI;
+    int i;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];       // or use: pI = MyArray;
+
+    // Use loop to display values
+    for ( i = 0 ; i < 10 ; i++ )
+    {
+        printf ("Value at index %d (direct access to the arrays) is: %d\n", i, MyArray[i]);
+        printf ("Value at index %d (access via the pointer) is: %d\n", i, pI[i]);
+    }
+
+    return 0;   // Exit
+}

Exercises/C15/pointer_array_example_4.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare an integer array and an integer pointer
+    int MyArray[10];
+    int *pI;
+    int i;
+
+    // Get the start address  by asking for the address iof array item [0]
+    pI = &MyArray[0];       // or use: pI = MyArray;
+
+    // Use loop to display values
+    for ( i = 0 ; i < 10 ; i++ )
+    {
+        //  Set the value then use the increment operator to move the pointer
+        //  to the next memory location. you can picture this as two steps: '
+        //
+        //      *pI = 5 + 4*i;
+        //  then
+        //      *pI++;
+
+        *pI++ = 5 + 4*i;	// set value at index[i] to 5+4*i
+    }
+
+	// Display the values placed in the array
+    for ( i = 0 ; i < 10 ; i++)
+    {
+        printf("%d ", MyArray[i]);
+    }
+    return 0;   // Exit
+}

Exercises/C16/alloc_example_1.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare an integer array and an integer pointer
+    int *pData;
+
+    // Using malloc
+    pData = malloc ( 10000 * sizeof (int));
+
+    // Using calloc
+    pData = calloc ( 10000 , sizeof (int));
+
+    return 0;   // Exit
+}

Exercises/C16/alloc_example_2.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare an integer array and an integer pointer
+    int *pData;
+
+    pData = calloc ( 10000 , sizeof (float));           // No warning
+    pData = (float *)calloc ( 10000 , sizeof (float));  // Warning
+
+    return 0;   // Exit
+}

Exercises/C16/alloc_example_3.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare an integer array and an integer pointer
+    int *pData;
+
+    // Using calloc (same approach malloc)
+    pData = calloc ( 10000 , sizeof (int));
+
+    if ( pData == NULL)
+    {
+        printf ("\nMemory could not be allocated - terminating");
+        return -1;  // Use minus one as we did not exit successfully
+    }
+    
+    // We have our  memory, make use of it here!
+    
+    return 0;   // Exit successfully
+}

Exercises/C16/alloc_example_4.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare an integer array and an integer pointer
+    int *pData;
+
+    // Using calloc (same approach malloc)
+    pData = calloc ( 10000 , sizeof (int));
+
+    if ( pData == NULL)
+    {
+        printf ("\nMemory could not be allocated - terminating");
+        return -1;  // Use minus one as we did not exit sucesfully
+    }
+
+     // We have our  memory, make use of it here!
+
+    // Free up the allocated memoey
+    free (pData);
+
+    return 0;   // Exit sucesfully
+}

Exercises/C16/ex2.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare an integer array and an integer pointer
+    int *pData;
+    int datlen;
+
+    printf("Length of data to be allocated: ");
+    scanf("%d", &datlen);
+
+    // Using malloc
+    pData = malloc ( datlen * sizeof (int));
+
+    free(pData);
+    return 0;   // Exit
+}

Exercises/C16/ex3.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare an integer array and an integer pointer
+    int *pData;
+    int datlen;
+
+    printf("Length of data to be allocated: ");
+    scanf("%d", &datlen);
+
+    // Using malloc
+    pData = malloc ( datlen * sizeof (int));
+
+    for (int i = 0; i < datlen; i++) {
+	    pData[i] = i;
+	    printf("%d %d\n", i, i);
+    }
+
+    free(pData);
+    return 0;   // Exit
+}

Exercises/C17/ArraysToFunctions1/arrays_to_functions_example_1.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Simple function to populate an integer array 
+void PopulateTheArray ( int Size, int ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        ArrayData[i] = 2*i + 1; // Treat it like a normal array
+    }
+}
+
+
+// Simple function to display contents of an integer array
+void DisplayTheArray ( int Size, int ArrayData[])
+{
+    int i;      // Variable to use in our loop
+ 
+    for ( i = 0 ; i < Size ; i++)
+    {
+        printf ("Item %d of the array contains %d\n", i, ArrayData[i]);
+    }
+}
+
+// Main () - execution starts here
+int main (void)
+{
+    int Data[10];
+
+    // Pass the size of the array and the array to our function - 					
+    // remembering that the array name on its own is the base address, 
+    // and so is the same as passing &Data[0]
+
+    PopulateTheArray(10, Data);
+    DisplayTheArray(10, Data);
+
+    return (0);     // Exit indicating sucess
+}

Exercises/C17/ArraysToFunctions2/arrays_to_functions_example_2.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Simple function to populate an integer array
+void PopulateTheArray ( int Size, int ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        ArrayData[i] = 2*i + 1; // Treat it like a normal array
+    }
+}
+// Simple function do display contents an integer array
+void DisplayTheArray ( int Size, int ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        printf ("Item %d of the array contains %d\n", i, ArrayData[i]);
+    }
+}
+// Main () - execution starts here
+int main (void)
+{
+
+    int iSizeForArray;
+    int *pData;              // A pointer to hold the base address of out array
+
+    // Ask for the size of the array and store result
+
+    printf("\nPlease enter the size of the array to dynamically allocate");
+    scanf ("%d", &iSizeForArray);
+
+    // Use calloc with checking
+    pData = calloc ( iSizeForArray, sizeof (int));
+
+    // Check we got the memory
+    if ( pData == NULL)
+    {
+        printf ("\nSorry, I could not allocate the memory, bye!");
+        return -1;
+    }
+
+    // Pass the size, iSizeForArray) and the pointer created 
+    // which points to the start of the sucesfully allocated memory
+
+    PopulateTheArray(iSizeForArray, pData);
+    DisplayTheArray(iSizeForArray, pData);
+
+    free (pData);	    // Free up the memory before exiting
+
+    return (0);     // Exit indicating sucess
+}

Exercises/C17/ex2.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+
+// Simple function to populate an integer array
+void PopulateTheArray ( int Size, float ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        ArrayData[i] = degrees_to_radians(i); // Treat it like a normal array
+    }
+}
+// Simple function do display contents an integer array
+void DisplayTheArray ( int Size, float ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        printf ("%d\t%0.3f\n", i, ArrayData[i]);
+    }
+}
+// Main () - execution starts here
+int main (void)
+{
+
+    int iSizeForArray;
+    float *pData;              // A pointer to hold the base address of out array
+
+    // Ask for the size of the array and store result
+
+    printf("Please enter the size of the array to dynamically allocate: ");
+    scanf ("%d", &iSizeForArray);
+
+    // Use calloc with checking
+    pData = calloc( iSizeForArray, sizeof (float));
+
+    // Check we got the memory
+    if ( pData == NULL)
+    {
+        printf ("Sorry, I could not allocate the memory, bye!\n");
+        return -1;
+    }
+
+    // Pass the size, iSizeForArray) and the pointer created 
+    // which points to the start of the sucesfully allocated memory
+
+    PopulateTheArray(iSizeForArray, pData);
+    DisplayTheArray(iSizeForArray, pData);
+
+    free(pData);	    // Free up the memory before exiting
+
+    return (0);     // Exit indicating sucess
+}

Exercises/C18/BinaryFile/binary_file_example.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main () - execution starts here
+int main (void)
+{
+
+    // Declate file stream variables
+    FILE *fInput, *fOutput;
+
+    // Other variables needed
+    int i;
+    int SampleArray[10] = {1,2,3,4,5,6,7,8,9,10};
+    float f = 23.4;
+
+    // Try and open the binary "numbers.dat" (in the current directory) file for writing
+    fOutput = fopen ("numbers.dat", "wb");
+
+    // Check we were able to open the file
+    if ( fOutput == NULL)
+    {
+        printf ("\nThe file could not be opened for writing, exiting");
+        return -1;
+    }
+
+    // Write out a single float to the binary file
+    fwrite ( &f, sizeof(float), 1 , fOutput);
+
+    // Now the entire array on one go
+    fwrite ( SampleArray, sizeof(int), 10 , fOutput);
+
+    // And close the file
+    fclose (fOutput);
+
+
+    // Try and open the binary "numbers.dat" (in the current directory) file for reading
+    fInput = fopen ("numbers.dat", "rb");
+
+    // Check we were able to open the file
+    if ( fInput== NULL)
+    {
+        printf ("\nthe file could not be opened for reading, exiting");
+        return -1;
+    }
+
+    // Read a single float from the binary file into f
+    fread ( &f, sizeof(float), 1 , fOutput);
+
+    // Now read the entire array on one go
+    fread ( SampleArray, sizeof(int), 10 , fOutput);
+
+    // Display the values read from the file on the screen
+    printf ("The value read into f is %f\n", f);;
+    for ( i = 0 ; i < 10 ; i++)
+    {
+        printf ("Item %d of the array contains %d\n",i, SampleArray[i]);
+    }
+
+    // And close the file
+    fclose (fInput);
+
+
+    return (0);     // Exit indicating sucess
+}

Exercises/C18/FileOpen/file_open_example.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main () - execution starts here
+int main (void)
+{
+
+    // Declate file stream variables
+    FILE *fInput, *fOutput, *fRecords;
+
+
+    // Try and open the text "sample.txt" (in the current directory) file for reading
+    fInput = fopen ("sample.txt", "r");
+
+    // Check we were able to open the file
+    if ( fInput == NULL)
+    {
+        printf ("\nthe file could not be opened");
+        return -1;	// Exit as unsuccessful 
+    }
+    
+	fclose (fInput);	// Close the file
+
+    // Try and open the binary "samples.dat" (in the current directory) file for writing
+    // if a file of this name already exists it will be deleted
+    fOutput = fopen ("samples.dat", "wb");
+
+    // Check we were able to open the file
+    if ( fOutput == NULL)
+    {
+        printf ("\nthe file could not be opened");
+		return -1;	// Exit as unsuccessful 
+    }
+
+	fclose (fOutput);	// Close the file
+
+    // Open, for appending, the text file "records.txt". If the file does not already
+    // exists, a new one of this name will be created (as if "w") were the mocde
+    fRecords = fopen ("records.txt", "a");
+
+    // Check we were able to open the file
+    if ( fRecords == NULL)
+    {
+        printf ("\nthe file could not be opened");
+		return -1;	// Exit as unsuccessful 
+    }
+
+	fclose (fRecords);
+
+
+    return (0);     // Exit indicating sucess
+}

Exercises/C18/TextFile/numbers.txt

@@ -0,0 +1,10 @@
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10

Exercises/C18/TextFile/text_file_example.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main () - execution starts here
+int main (void)
+{
+    // Declate file stream variables
+    FILE *fInput, *fOutput;
+
+    // Other variables needed
+    int i,d;
+
+    // Try and open the text "sample.txt" (in the current directory) file for writing
+    fOutput = fopen ("numbers.txt", "w");
+
+    // Check we were able to open the file
+    if ( fOutput == NULL)
+    {
+        printf ("\nthe file could not be opened for writing, exiting");
+        return -1;
+    }
+
+    // Use a loop to write values to the newly created file
+    for ( i = 1 ; i <= 10 ; i++)
+    {
+        fprintf (fOutput, "%d\n", i);
+    }
+
+    // And close the file
+    fclose (fOutput);
+
+    // Try and open the binary "numbers " (in the current directory) file for reading
+
+    fInput = fopen ("numbers.txt", "r");
+
+    // Check we were able to open the file
+    if ( fInput == NULL)
+    {
+        printf ("\nthe file could not be opened for reading, exiting");
+        return -1;
+    }
+ 
+    // Read, line by line the 10 values written into variable d
+    // and then display the contents of d on the screen
+    for ( i = 1 ; i <= 10 ; i++)
+    {
+        fscanf (fInput, "%d", &d);
+        printf ("Value read from file %d\n",d);
+    }
+
+    // And close the file
+    fclose (fInput);
+
+    return (0);     // Exit indicating success
+}

Exercises/C18/ex2.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main () - execution starts here
+int main (void)
+{
+    // Declate file stream variables
+    FILE *fInput, *fOutput;
+
+    // Other variables needed
+    int i, d, d2;
+
+    // Try and open the text "sample.txt" (in the current directory) file for writing
+    fOutput = fopen ("numbers.txt", "w");
+
+    // Check we were able to open the file
+    if ( fOutput == NULL)
+    {
+        printf ("The file could not be opened for writing, exiting\n");
+        return -1;
+    }
+
+    // Use a loop to write values to the newly created file
+    for ( i = 1 ; i <= 10 ; i++)
+    {
+        fprintf (fOutput, "%d %d\n", i, i*i);
+    }
+
+    // And close the file
+    fclose (fOutput);
+
+    // Try and open the binary "numbers " (in the current directory) file for reading
+
+    fInput = fopen ("numbers.txt", "r");
+
+    // Check we were able to open the file
+    if ( fInput == NULL)
+    {
+        printf ("The file could not be opened for reading, exiting\n");
+        return -1;
+    }
+ 
+    // Read, line by line the 10 values written into variable d
+    // and then display the contents of d on the screen
+    for ( i = 1 ; i <= 10 ; i++)
+    {
+        fscanf (fInput, "%d %d", &d, &d2);
+        printf ("Value read from file: %d %d\n", d, d2);
+    }
+
+    // And close the file
+    fclose (fInput);
+
+    return (0);     // Exit indicating success
+}

Exercises/C18/ex3.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Main () - execution starts here
+int main (void)
+{
+    // Declate file stream variables
+    FILE *fInput, *fOutput;
+    // 8x the maximum filename length on most filesystems should be a decent size
+    char filename[2049] = { 0 };
+
+    printf("Enter filename: ");
+    scanf("%2048s", filename);
+
+    // Other variables needed
+    int i, d, d2;
+
+    // Try and open the text "sample.txt" (in the current directory) file for writing
+    fOutput = fopen (filename, "w");
+
+    // Check we were able to open the file
+    if ( fOutput == NULL)
+    {
+        printf ("The file could not be opened for writing, exiting\n");
+        return -1;
+    }
+
+    // Use a loop to write values to the newly created file
+    for ( i = 1 ; i <= 10 ; i++)
+    {
+        fprintf (fOutput, "%d %d\n", i, i*i);
+    }
+
+    // And close the file
+    fclose (fOutput);
+
+    // Try and open the binary "numbers " (in the current directory) file for reading
+
+    fInput = fopen ("numbers.txt", "r");
+
+    // Check we were able to open the file
+    if ( fInput == NULL)
+    {
+        printf ("The file could not be opened for reading, exiting\n");
+        return -1;
+    }
+ 
+    // Read, line by line the 10 values written into variable d
+    // and then display the contents of d on the screen
+    for ( i = 1 ; i <= 10 ; i++)
+    {
+        fscanf (fInput, "%d %d", &d, &d2);
+        printf ("Value read from file: %d %d\n", d, d2);
+    }
+
+    // And close the file
+    fclose (fInput);
+
+    return (0);     // Exit indicating success
+}

Exercises/C18/ex4.c

@@ -0,0 +1,92 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+
+// Simple function to populate an integer array
+void PopulateTheArray ( int Size, float ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        ArrayData[i] = degrees_to_radians(i); // Treat it like a normal array
+    }
+}
+// Simple function do display contents an integer array
+void DisplayTheArray ( int Size, float ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        printf ("%d\t%0.3f\n", i, ArrayData[i]);
+    }
+}
+
+int SaveArray (char *filename, int Size, float ArrayData[])
+{
+	FILE *fp;   // File Pointer
+	int i;      // Variable to use in our loop
+
+	fp = fopen(filename, "w");
+	// if file open failed, return error to caller
+	if (fp == NULL) {
+		return 1;
+	}
+
+
+	for ( i = 0 ; i < Size ; i++)
+	{
+		fprintf(fp, "%d\t%0.3f\n", i, ArrayData[i]);
+	}
+
+	// close file, returns 0 on successful closing (therefore function has executed sucessfully)
+	return fclose(fp);
+}
+// Main () - execution starts here
+int main (void)
+{
+    char filename[2049];
+    int rc, iSizeForArray;
+    float *pData;              // A pointer to hold the base address of out array
+
+    // Ask for the size of the array and store result
+
+    printf("Please enter the size of the array to dynamically allocate: ");
+    scanf ("%d", &iSizeForArray);
+
+    // Use calloc with checking
+    pData = calloc( iSizeForArray, sizeof (float));
+
+    // Check we got the memory
+    if ( pData == NULL)
+    {
+        printf ("Sorry, I could not allocate the memory, bye!\n");
+        return -1;
+    }
+
+    // Pass the size, iSizeForArray) and the pointer created 
+    // which points to the start of the sucesfully allocated memory
+
+    PopulateTheArray(iSizeForArray, pData);
+    DisplayTheArray(iSizeForArray, pData);
+
+    // Exercise doesn't ask to use function but kind of pointless without
+    printf("Enter filename: ");
+    scanf("%2048s", filename);
+    rc = SaveArray(filename, iSizeForArray, pData);
+    if (rc != 0) {
+	    printf("Error saving file\n");
+	    free(pData);
+	    return rc;
+    }
+
+    free(pData);	    // Free up the memory before exiting
+    return (0);     // Exit indicating sucess
+}

Exercises/C18/ex5.c

@@ -0,0 +1,88 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+
+float degrees_to_radians(float degrees) {
+	return M_PI * degrees / 180.0;
+}
+
+
+// Simple function to populate an integer array
+void PopulateTheArray ( int Size, float ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        ArrayData[i] = degrees_to_radians(i); // Treat it like a normal array
+    }
+}
+// Simple function do display contents an integer array
+void DisplayTheArray ( int Size, float ArrayData[])
+{
+    int i;      // Variable to use in our loop
+
+    for ( i = 0 ; i < Size ; i++)
+    {
+        printf ("%d\t%0.3f\n", i, ArrayData[i]);
+    }
+}
+
+int SaveArrayBinary (char *filename, int Size, float ArrayData[])
+{
+	FILE *fp;   // File Pointer
+	int i;      // Variable to use in our loop
+
+	fp = fopen(filename, "wb");
+	// if file open failed, return error to caller
+	if (fp == NULL) {
+		return 1;
+	}
+
+	// write data
+	fwrite(ArrayData, sizeof(float), Size, fp);
+	// close file, returns 0 on successful closing (therefore function has executed sucessfully)
+	return fclose(fp);
+}
+// Main () - execution starts here
+int main (void)
+{
+	char filename[2049];
+	int rc, iSizeForArray;
+	float *pData;              // A pointer to hold the base address of out array
+
+	// Ask for the size of the array and store result
+
+	printf("Please enter the size of the array to dynamically allocate: ");
+	scanf ("%d", &iSizeForArray);
+
+	// Use calloc with checking
+	pData = calloc( iSizeForArray, sizeof (float));
+
+	// Check we got the memory
+	if ( pData == NULL)
+	{
+		printf ("Sorry, I could not allocate the memory, bye!\n");
+		return -1;
+	}
+
+	// Pass the size, iSizeForArray) and the pointer created 
+	// which points to the start of the sucesfully allocated memory
+
+	PopulateTheArray(iSizeForArray, pData);
+	DisplayTheArray(iSizeForArray, pData);
+
+	// Exercise doesn't ask to use function but kind of pointless without
+	printf("Enter filename: ");
+	scanf("%2048s", filename);
+	rc = SaveArrayBinary(filename, iSizeForArray, pData);
+	if (rc != 0) {
+		printf("Error saving file\n");
+		free(pData);
+		return rc;
+	}
+
+	free(pData);    // Free up the memory before exiting
+	return (0);     // Exit indicating sucess
+}

Exercises/C18/ex6.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+
+int main() {
+	FILE *fp;                    // file pointer
+	float *data;                 // data pointer (array of floats)
+	int i, file_size, arr_size;
+	char filename[2049];
+
+	printf("Enter filename to read: ");
+	scanf("%2048s", filename);
+
+	fp = fopen(filename, "rb");
+	if (fp == NULL) {
+		printf("Failed to open file\n");
+		return 1;
+	}
+
+	// get file size (technically isn't the best way because SEEK_END is undefined behaviour:
+	//
+	// "Library implementations are allowed to not meaningfully support SEEK_END
+	// (therefore, code using it has no real standard portability)."
+	// ~ https://cplusplus.com/reference/cstdio/fseek/
+	//
+	// " Setting the file position indicator to end-of-file, as with fseek(file, 0, SEEK_END),
+	// has undefined behavior for a binary stream (because of possible trailing null characters) or
+	// for any stream with state-dependent encoding that does not assuredly end in the initial shift
+	// state. "
+	// ~ https://port70.net/~nsz/c/c11/n1570.html#note268
+	//
+	// it is also limited to 2GB files as it returns a signed integer
+	// better to use something like this probably:
+	// https://stackoverflow.com/a/238609
+	//
+	// but louise uses fseek so i will too
+	fseek(fp, 0, SEEK_END);
+	file_size = ftell(fp);
+	arr_size = file_size/sizeof(float);
+	rewind(fp);
+
+	// allocate memory and read data
+	data = malloc(file_size);
+	fread(data, sizeof(float), arr_size, fp);
+
+	for (i = 0; i < arr_size; i++) {
+		printf("%d %0.3f\n", i, data[i]);
+	}
+
+	free(data);
+}

Exercises/C19/DefineExamples/define_example.c

@@ -0,0 +1,18 @@
+#define UP 1
+#define DOWN 2
+
+int main()
+{
+    int i = 1;
+    
+    if (i == UP )
+    {
+        // Do something
+    }
+    
+    if ( i == DOWN)
+    {
+        // Doe something else
+    }
+    return 0;
+}

Exercises/C19/enum_example.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+enum DOW { sun, mon, tue, wed, thu, fri, sat } ;
+
+// Main () - execution starts here
+int main (void)
+{
+    enum DOW day;
+
+    /* Code that get a value for 'day' */
+    day = tue;
+
+    switch (day)
+    {
+        case sun : printf ("Sunday\n") ; break ;
+        case mon : printf ("Monday\n") ; break ;
+        case tue : printf ("Tuesday\n") ; break ;
+        /* etc. */
+    }
+    return (0);     // Exit indicating success
+}

Exercises/C19/ex1.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+
+struct Person {
+	int age;
+	char forename[30];
+	char surname[50];
+};
+
+
+int main() {
+	struct Person p;
+
+	printf("Enter age: "); scanf("%d", &p.age);
+	printf("Enter forename: "); scanf("%29s", p.forename);
+	printf("Enter surname: "); scanf("%49s", p.surname);
+
+	printf("p.age=%d p.forename=%s p.surname=%s\n", p.age, p.forename, p.surname);
+	return 0;
+}

Exercises/C19/ex2.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+
+
+struct Person {
+	int age;
+	char forename[30];
+	char surname[50];
+};
+
+
+void print_person(struct Person p) {
+	printf("p.age=%d p.forename=%s p.surname=%s\n", p.age, p.forename, p.surname);
+}
+
+
+int main() {
+	struct Person p;
+
+	printf("Enter age: "); scanf("%d", &p.age);
+	printf("Enter forename: "); scanf("%29s", p.forename);
+	printf("Enter surname: "); scanf("%49s", p.surname);
+
+	print_person(p);
+	return 0;
+}

Exercises/C19/ex3.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+
+
+struct Person {
+	int age;
+	int year_of_birth;
+	char forename[30];
+	char surname[50];
+};
+
+
+void print_person(struct Person p) {
+	printf("p.age=%d p.year_of_birth=%d p.forename=%s p.surname=%s\n", p.age, p.year_of_birth, p.forename, p.surname);
+}
+
+
+int main() {
+	struct Person p;
+
+	printf("Enter age: "); scanf("%d", &p.age);
+	printf("Enter birth year: "); scanf("%d", &p.year_of_birth);
+	printf("Enter forename: "); scanf("%29s", p.forename);
+	printf("Enter surname: "); scanf("%49s", p.surname);
+
+	print_person(p);
+	return 0;
+}

Exercises/C19/ex4.c

@@ -0,0 +1,50 @@
+#include <stdio.h>
+
+
+struct Person {
+	int age;
+	int year_of_birth;
+	char forename[30];
+	char surname[50];
+};
+
+
+void print_person(struct Person p) {
+	printf("p.age=%d p.year_of_birth=%d p.forename=%s p.surname=%s\n", p.age, p.year_of_birth, p.forename, p.surname);
+}
+
+
+int main() {
+	struct Person p;
+	FILE *fp;
+	char choice;
+	char filename[4097];
+
+	printf("Read or write a file? (r/w) "); scanf("%c", &choice);
+
+	if (choice == 'w') {
+		printf("Enter age: "); scanf("%d", &p.age);
+		printf("Enter birth year: "); scanf("%d", &p.year_of_birth);
+		printf("Enter forename: "); scanf("%29s", p.forename);
+		printf("Enter surname: "); scanf("%49s", p.surname);
+
+		printf("Enter filename to save to: "); scanf("%4096s", filename);
+		fp = fopen(filename, "wb");
+		if (fp == NULL) {
+			printf("Failed to open file for writing\n");
+			return 1;
+		}
+		fwrite(&p, 1, sizeof(p), fp);
+	} else {
+		printf("Enter file to read from: "); scanf("%4096s", filename);
+		fp = fopen(filename, "rb");
+		if (fp == NULL) {
+			printf("Failed to open file for reading\n");
+			return 1;
+		}
+		fread(&p, 1, sizeof(p), fp);
+	}
+
+	print_person(p);
+	return 0;
+}

Exercises/C19/static_variable_example.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void DisplayHelloWorld (void)
+{
+    static int k = 0;       // Counter for how many times the function is called
+
+    printf ("Hello World\n");
+
+    // Increment counter and display value
+    k = k + 1;
+    printf ("I have now said this %d times\n",k);
+}
+// Main () - execution starts here
+int main (void)
+{
+    int i;
+
+    // Loop calling out function 10 times
+    for ( i =0 ; i < 10 ; i++ )
+    {
+        DisplayHelloWorld();
+    }
+
+    return (0);     // Exit indicating success
+}

Exercises/C20/ConditionalDirective/conditional_directive_example.c

@@ -0,0 +1,15 @@
+#include <stdio.h>  
+#include <conio.h>  
+
+#define DEBUG_ON 0
+
+int main(void) 
+{  
+#if DEBUG_ON == 1
+	printf("Debug mode - about to do something\n");  
+#else  
+	printf("Running in standard mode");  
+#endif  
+	
+	return 0;
+}

Exercises/C20/FormattingDirective/formatting_directive_example.c

@@ -0,0 +1,15 @@
+#include <stdio.h>  
+#include <conio.h>  
+
+//#define DEBUG_ON 0
+
+int main(void) 
+{  
+#ifdef DEBUG_ON 
+	printf("Debug mode - about to do something\n");  
+#else  
+	printf("Running in standard mode");  
+#endif         
+
+return 0;
+} 

Exercises/C20/macro_function_example.c

@@ -0,0 +1,8 @@
+#include <stdio.h>  
+#define MIN(a,b) ((a)<(b)?(a):(b))  
+
+int main(void) 
+{  
+   printf("The minimum value of 10 and 20 is: %d\n", MIN(10,20));    
+   return 0;
+}

Exercises/C21/sprintf_example.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main()
+{
+    int i;
+    char FileName[100];
+
+    for ( i = 1 ; i < 10 ; i++)
+    {
+        //'Print' text into string
+        sprintf(FileName , "file%d.dat" , i);
+
+        // Sidplay the name created
+        printf("Current file name: %s\n", FileName);
+    }
+
+    return 0;
+}

Exercises/C3/hello_world.c

@@ -0,0 +1,10 @@
+#include <stdlib.h>
+#include <stdio.h>
+ 
+/* My first program */
+int main(void)
+{
+  // This is a single line of comment
+  printf("Hello World\n");
+  return 0;
+}

Exercises/C4/Correct_answer/correct_answer.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare and initialise as required
+    int a = 1,b = 4;
+    float ans;
+
+    // Perform calculation 
+    // This time a & b are  treated as if they are floats
+    // the result of this float calculation is stored in ans
+    ans = (float)a / (float)b;
+
+    // Display answer
+    printf ("\nThe answer is %f",ans);
+
+    return 0;
+
+}

Exercises/C4/Wrong_answer/wrong_answer.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare and initialise as required
+    int a = 1,b = 4;
+    float ans;
+
+    // Perform calculation 
+    // a and b are integers so the answer will be the result of the integer division
+    
+    ans = a / b;
+
+    // Display answer
+    printf ("\nThe answer is %f",ans);
+
+    return 0;
+
+}

Exercises/C4/declare_a_string.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main(void)
+{
+	// A variable to store a name (maximum 49 characters)
+	char Name[50];
+    
+	// Declare multiple strings on the same line 
+	char AddressLine1[100], AddressLine2[100], PostCode[10];
+
+	// all done
+	return 0;
+}

Exercises/C4/difficult_to_read_code.c

@@ -0,0 +1,4 @@
+#include <stdio.h>
+int main(void) { int revenue = 80; int cost = 50; int roi; 
+roi = (100 * (revenue - cost)) / cost; if (roi >= 0) { 
+printf ("%d\n", roi); } return 0; }

Exercises/C4/poor_layout/poor_layout.c

@@ -0,0 +1,4 @@
+#include <stdio.h>
+
+ /* My first program */
+int main(void) { printf("Hello World");  return 0; }

Exercises/C4/reformatted_code.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+int main(void) 
+{
+	// Declare variables and give initial values 
+	int revenue = 80;
+	int cost = 50;
+	int roi;
+	
+	// Perform calculation
+	roi = (100 * (revenue - cost)) / cost;
+	
+	// Make decision based on value of roi
+	if (roi >= 0) 
+	{
+		printf ("%d\n", roi);
+	}
+
+	return 0;	// Exit indicating success
+}

Exercises/C4/simple_claculation.c

@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main(void)
+{
+    int a = 6,b = 7,c; // Declare and initialiase as required
+    c = a + b;         // Add the values and store in c
+
+}

Exercises/C4/well_laid_out_code.c

@@ -0,0 +1,8 @@
+#include <stdio.h>
+
+/* My first program */
+int main(void)
+{
+  printf("Hello World");
+  return 0;
+}

Exercises/C5/FormattingNumbers/formatting_numbers.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int a = 123;
+    float f = 12.456f;
+
+    // Use printf display text on the screen
+    printf ("Examples of integer formatting\n");
+    printf ("a = %d (no modifier)\n", a);
+    printf ("a = %6d (w:6, justify:right)\n", a);
+    printf ("a = %-6d (w:6 )\n", a);
+
+    // Use printf display text on the screen
+    printf ("Examples of float formatting\n");
+    printf ("f = %f (no modifier)\n", f);
+    printf ("f = %6.2f (w:6, 2dp, justify:right)\n", f);
+    printf ("f = %-6.1f (w:6, 1dp)\n", f);
+
+    // Exit from main
+    return 0;
+}

Exercises/C5/displaying_variables.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int a = 1, b = 2;
+    float f = 1.23f;
+
+    // Use printf display text on the screen
+    printf ("The variables are\na = %d\nb=%d\nf=%f", a, b, f);
+
+    // Exit from main
+    return 0;
+}

Exercises/C5/ex4.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+	float r;
+	printf("Enter radius: ");
+	scanf("%f", &r);
+
+	printf("Area of sphere: %f\n", 4.0*M_PI*r*r);
+	printf("Volume of sphere: %f\n", M_PI*r*r*r*4.0/3.0);
+}

Exercises/C5/ex5.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+	float r;
+	printf("Enter radius: ");
+	scanf("%f", &r);
+
+	printf("Area of circle: %0.2f\n", M_PI*r*r);
+	printf("Volume of sphere: %.02f\n", M_PI*r*r*r*4.0/3.0);
+}

Exercises/C5/not_displaying.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+
+    // Declare some variables
+    int a = 1, b = 2;
+    float f = 1.23f;
+
+    // Use printf display text on the screen
+    printf ("The variables are a, b and f");
+
+    // Exit from main
+    return 0;
+
+}

Exercises/C5/printf_example_1.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{ 
+    
+    printf ("This is my first computer program"); 
+    printf ("Hello World");
+
+    return 0;
+
+}

Exercises/C5/printf_example_2.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    
+    printf ("This is my first computer program\n");
+    printf ("Hello World\n");
+
+    return 0;
+
+}

Exercises/C6/ex1.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int  a, b;
+
+    // Note: Order of a,b indicates the order in which operations are carried out on execution
+    
+    // Increment operators
+    b = 3;
+    printf("a=%d b=%d\n", a, b);
+    a = ++b;    // b is now 4, a is also 4
+    printf("a=%d b=%d\n", a, b);
+    a = b++;    // a is 4, b is now 5, 
+    printf("a=%d b=%d\n", a, b);
+    
+    // Decrement operators (reset a back to 3)
+    b = 3;
+    printf("a=%d b=%d\n", a, b);
+    a = b--;    // a is 3, b is now 2    
+    printf("a=%d b=%d\n", a, b);
+    a = --b;    // b is now 1, a is also 1
+    printf("a=%d b=%d\n", a, b);
+    
+    return 0;	// Exit from main
+}

Exercises/C6/ex2.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main() {
+	unsigned int a = 60;
+	unsigned int b = 13;
+	unsigned int r;
+
+	r = a & b;
+	printf("bitwise AND of 60 and 13: %d\n", r);
+	r = a | b;
+	printf("bitwise OR of 60 and 13: %d\n", r);
+	r = a ^ b;
+	printf("bitwise XOR of 60 and 13: %d\n", r);
+}

Exercises/C6/ex3.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main() {
+	unsigned int a = 0x60;
+	unsigned int b = 0x13;
+	unsigned int r;
+
+	r = a & b;
+	printf("bitwise AND of 0x60 and 0x13: 0x%02x\n", r);
+	r = a | b;
+	printf("bitwise OR of 0x60 and 0x13: 0x%02x\n", r);
+	r = a ^ b;
+	printf("bitwise XOR of 0x60 and 0x13: 0x%02x\n", r);
+}

Exercises/C6/inc_dec_examples.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int  a, b;
+
+    // Note: Order of a,b indicates the order in which operations are carried out on execution
+    
+    // Increment operators
+    b = 3;
+    a = ++b;    // b is now 4, a is also 4
+    a = b++;    // a is 4, b is now 5, 
+    
+    // Decrement operators (reset a back to 3)
+    b = 3;
+    a = b--;    // a is 3, b is now 2    
+    a = --b;    // b is now 1, a is also 1
+    
+    return 0;	// Exit from main
+}

Exercises/C7/Getchar/getchar_example.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // declare variable
+    char c;
+
+    printf("Input a character: ");
+    // Wait for a kepypress, store result in c
+    c = getchar();
+
+    // Display on the screen using printf
+    printf ("The charcter pressed was %c\n", c);
+
+    // Display the charcter using putchar()
+    putchar(c);
+    
+    return 0;	    // Exit from main
+}

Exercises/C7/Scanf1/scanf_example_1.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    int a;		    // Declare some variables
+    float f;
+
+    // Use printf to prompt the use to enter an integer
+    printf ("Please enter an integer\n");
+    
+    // use scanf with %d to read into 'a' 
+    scanf ("%d",&a);	// note the important & 
+    
+    // And display on the screen
+    printf ("The value you entered for a is %d\n", a);
+    
+	// Use printf to prompt the use to enter an float
+    printf ("Please enter a float\n");
+    
+    // use scanf with %f to read into 'f' 
+    scanf ("%f",&f);  // note the important & 
+    
+    // And display on the screen
+    printf ("The value you entered for f is %f\n", f);
+
+    return 0;     // Exit from main
+}

Exercises/C7/Scanf2/scanf_example_2.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+
+int main(void)
+{
+    // Declare some variables
+    int a,b,c;
+    float f,g;
+
+    // Use printf to prompt the use to enter 3 integers
+    printf ("Please enter three integer\n");
+    
+    // use scanf with %d to read into a, b and c
+    scanf ("%d %d %d",&a, &b, &c);	// note the important & 
+    
+    // And display on the screen
+    printf ("The values entered were %d %d %d\n", a, b, c);
+    
+	// Use printf to prompt the use to enter an float
+    printf ("Please enter two floats\n");
+    
+	// use scanf with %f to read into f ang g
+    scanf ("%f %f",&f, &g);  // note the important & 
+    
+	// And display on the screen
+    printf ("The value you entered were %f and %f \n", f,g);
+    
+    return 0;	// Exit from main
+}

Exercises/C7/ex2.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+	float r;
+	printf("Enter radius: ");
+	scanf("%f", &r);
+
+	printf("Area of circle: %f\n", M_PI*r*r);
+	printf("Volume of sphere: %f\n", M_PI*r*r*r*4.0/3.0);
+}

Exercises/C7/ex3.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+	float radius, height;
+
+	printf("Enter radius: ");
+	scanf("%f", &radius);
+	printf("Enter height: ");
+	scanf("%f", &height);
+
+	printf("Surface area: %f\n", 2*M_PI*radius*radius + 2*M_PI*radius*height);
+}

Exercises/C7/ex4.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+
+int main() {
+	char name[200] = { 0 };
+
+	printf("What is your name? ");
+	scanf("%s", name);
+
+	printf("Hello %s\n", name);
+
+}

Exercises/C7/ex5.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main() {
+	char name[200] = { 0 };
+	int age = 0;
+
+	printf("What is your name? ");
+	scanf("%s", name);
+
+	printf("What is your age? ");
+	scanf("%ud", &age);
+
+	printf("Hello %s\nYou are %d years old\n", name, age);
+
+}

Exercises/C7/string_with_gets.c

@@ -0,0 +1,19 @@
+#include <stdio.h> 
+#include <stdlib.h>
+int main() 
+{ 
+	// Declare variable - maximum 99 characters
+    char str[100]; 
+    
+    // Prompt for text
+    printf("enter some text\n"); 
+    
+    // Store intput in str 
+    gets(str); 
+    
+    // Display a message on the screen
+    printf("you entered : %s\n", str); 
+    
+    // Exit from main
+    return 0; 
+} 

Exercises/C7/string_with_scanf.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    char name[50];
+
+    // Wait for a kepypress, store result in c
+    printf ("Please enter your name");
+
+    // read in using scanf with %s
+    scanf ("%s",name);
+
+    // Display on the screen using printf
+    printf ("Hello %s\n", name);
+
+    // Exit from main
+    return 0;
+}

Exercises/C8/ex2.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main() {
+	int input;
+
+	printf("Enter an integer: ");
+	scanf("%d", &input);
+
+	if (input >= 0 && input <= 10) {
+		printf("The number is in range\n");
+	}
+
+	return 0;
+}

Exercises/C8/ex3.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main() {
+	int input;
+
+	printf("Enter an integer: ");
+	scanf("%d", &input);
+
+	if (!(input >= 0 && input <= 10)) {
+		printf("The number is not in range\n");
+	}
+
+	return 0;
+}

Exercises/C8/ex4.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+int main() {
+	int age;
+
+	printf("Enter your age: ");
+	scanf("%d", &age);
+
+	// c only matches one branch so don't need to specify lower limits of each age range
+	if ( age <= 0 ) {
+		printf("Still a baby\n");
+	} else if ( age <= 12 ) {
+		printf("The junior years\n");
+	} else if ( age < 20 ) {
+		printf("Teenage years\n");
+	} else {
+		printf("Downhill all the way now!\n");
+	}
+
+	return 0;
+}

Exercises/C8/ex7.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+	int rc; // used to check return codes of scanf
+	float radius, height;
+
+	printf("Enter radius: ");
+	rc = scanf("%f", &radius);
+	// scanf returns number of scanned items. If input is invalid then 0 values will have been scanned.
+	if (rc != 1) {
+		printf("Please enter an positive real integer or decimal\n");
+		return 1;
+	}
+
+	printf("Enter height: ");
+	rc = scanf("%f", &height);
+	// scanf returns number of scanned items. If input is invalid then 0 values will have been scanned.
+	if (rc != 1) {
+		printf("Please enter an positive real integer or decimal\n");
+		return 1;
+	}
+
+	printf("Surface area: %f\n", 2*M_PI*radius*radius + 2*M_PI*radius*height);
+}

Exercises/C8/if_example.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	// Declare some variables
+	int  a = 7, b=6;
+
+	printf("Enter a value for a: ");
+	scanf("%d", &a);
+	printf("Enter a value for b: ");
+	scanf("%d", &b);
+
+	// A single line of code conditional on the value of a
+	if ( a == 7 )
+	   printf ("The value of a is 7 - so I will do this\n");
+	   
+	// Multiple lines of code conditional on b not equalling 4
+	// so then need to be placed inside { and }
+	if ( b != 4 )
+	{
+	   printf ("The value of b is not 4\n");
+	   printf ("So I will do multiple tasks\n");
+	}
+	   
+	return 0;   // Exit from main
+}

Exercises/C8/switch_example_1.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int a = 1;
+    switch ( a )
+    {
+    case 0 :
+        printf ("Sunday\n");
+        break ; // end of the lines of code to execute
+
+    case 1:
+        printf ("Monday\n");
+        break ; // end of the lines of code to execute
+
+    case 2:
+        printf ("Tuesday\n");
+        break ; // end of the lines of code to execute
+
+    // etc...
+
+    default: // If no case is met (OPTIONAL)
+        printf ("\nThe value supplied is out of range\n");
+
+    }
+    return 0;
+}

Exercises/C8/switch_example_2.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	// Declare some variables
+	int a = 1;
+	switch ( a )
+	{
+	case 1 :
+	case 2 : 
+	case 3 : 
+		// Code to do if a is 1, 2 or 3
+	break ; // end of the lines of code to execute
+
+	case 4:
+	case 5:
+		// Code to do if a is 4 or 5
+		break ; // end of the lines of code to execute
+
+	default: // If no case is met (OPTIONAL)
+		// Code to do if no case is met
+	}
+	return 0;
+}

Exercises/C8/switch_example_3.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int a = 1;
+    switch ( a )
+    {
+    case 1 :
+        printf ("This is case 1\n");
+    case 2 :
+        printf ("This is case 2\n");
+    case 3 :
+        printf ("This is case 3\n");
+        break ; // end of the lines of code to execute
+
+    default: // If no case is met
+        printf ("This default case\n");
+        // Code to do if no case is met
+    }
+    return 0;
+}

Exercises/C9/do_while_loop.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	int age;		// Declare variable, no need to initialise this time 
+					// as we read into it before it is tested against
+    
+    // The loop is always entered as the test is at the end
+    do 
+    {
+        // Code must be executed at least once
+        printf ("\nPlease enter your age");
+        scanf("%d", &age);
+        printf ("You are %d years old\n", age);    
+        
+        // Test is now made and the code 
+        // repeats if the test equates as non-zerp
+        // (i.e. is age is not zero)
+    }
+    while ( age != 0);
+    
+    return 0;
+}

Exercises/C9/ex2.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+   	int age = 1;  			// Declare variable and initialise to 1
+    
+    while ( age != 0)	    // Loop as long as age is not zero
+    {
+        // Code in {} executed if condition is true (non-zero)
+        
+        printf ("\nPlease enter your age: ");
+        scanf("%d", &age);
+        printf ("You are %d years old\n", age);
+
+	if (age == 18 || age == 21) {
+		printf("You have come of age\n");
+	}
+        
+        // Code  now goes back and repeats the test with the value of age just entered
+    }
+    return 0;	// Exit code
+}

Exercises/C9/ex3.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+#define MAX_NAME_LEN 200
+
+int main() {
+	char name[MAX_NAME_LEN] = { 0 };
+
+	printf("Please enter your name: ");
+	scanf("%s", name);
+
+	while (1) {
+		printf("%s\n", name);
+	}
+}

Exercises/C9/ex4.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	int age = 1; // Declare variable and initialise to 1
+
+	do {
+
+	printf ("\nPlease enter your age: ");
+	scanf("%d", &age);
+	printf ("You are %d years old\n", age);
+
+	if (age == 18 || age == 21) {
+		printf("You have come of age\n");
+	}
+
+	// Code  now goes back and repeats the test with the value of age just entered
+	} while ( age != 0); // Loop as long as age is not zero
+	return 0; // Exit code
+}

Exercises/C9/ex5.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int main() {
+	for (int i = 1; i <= 15; i++) {
+		printf("%d\n", i);
+	}
+
+	return 0;
+}

Exercises/C9/ex6.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+
+int main() {
+	int rc, start, end;
+
+	printf("Start: ");
+	rc = scanf("%d", &start);
+	if (rc != 1) {
+		printf("Please enter a real integer\n");
+		return 1;
+	}
+	printf("End: ");
+	rc = scanf("%d", &end);
+	if (rc != 1) {
+		printf("Please enter a real integer\n");
+		return 1;
+	}
+
+	if (start > end) {
+		printf("Please ensure that start value is smaller than end value\n");
+		return 1;
+	}
+
+	for (int i = start; i <= end; i++) {
+		printf("%d\n", i);
+	}
+
+	return 0;
+}