Added book examples

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);
+}

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
+}

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;
+}

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
+}

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
+}

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
+}

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;
+}

C13/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
+}

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;
+}

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
+}

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;
+}

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
+}

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
+}

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
+}

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
+}

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
+}

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
+}

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
+}

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
+}

C17/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 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 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
+}

C17/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
+}

C18/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
+}

C18/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
+}

C18/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
+}

C19/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;
+}

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
+}

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
+}

C20/conditional_directive_example.c

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

C20/formatting_directive_example.c

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

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;
+}

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;
+}

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");
+  return 0;
+}

C4/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;
+
+}

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;
+}

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; }

C4/poor_layout.c

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

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
+}

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
+
+}

C4/well_laid_out_code.c

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

C4/wrong_answer.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare and initialiase as required
+    int a = 1,b = 4;
+    float ans;
+
+    ans = a / b;	    // Perform calculation
+
+    // Display answer
+    printf ("\nThe answer is %f",ans);
+    
+    // Exit from program
+    return 0;
+}

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;
+}

C5/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;
+}

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;
+
+}

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;
+
+}

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;
+
+}

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
+}

C7/getchar_example.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // declare variable
+    char c;
+
+    // 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
+}

C7/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
+}

C7/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
+}

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; 
+} 

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;
+}

C8/if_example.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Declare some variables
+    int  a = 7, b=6;
+
+	// 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
+}

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;
+}

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;
+}

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;
+}

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;
+}

C9/for_loop_examples.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    // Ddeclare variable and initialise to 1
+    int i;
+
+    // Count up from 1 to 100 in steps of 1
+    // Note the test could also be: i <= 100
+    for ( i = 0 ; i < 101 ; i++ )
+    {
+        printf ("The value of i is %d\n",i);
+    }
+
+    // Count down form 10 to zero
+    // Note: we could also use the test: i != 0
+    for ( i = 10 ; i >= 0 ; i-- )
+    {
+        printf ("The value of i is %d\n",i);
+    }
+
+    // Count up from 1 to 100 in steps of 3
+    // Note the test could also be: i <= 100
+    // Increement could also be written as i+=3
+    for ( i = 0 ; i < 101 ; i=i+1 )
+    {
+        printf ("The value of i is %d\n",i);
+    }
+    return 0;
+}

C9/infinite_while_loop.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	int age ;  	// Declare variable, no need to initialise this time 
+				// as the test condition is not based on its value
+    
+    // This is always non-zero, the loop will never break
+    while ( 1 )
+    {
+        // 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);    
+        
+        // Code  now goes back and repeats 
+        // as the conditions is always non-zero (true)
+    }
+    
+    return 0;	// Exit code
+}

C9/while_loop.c

@@ -0,0 +1,19 @@
+#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);    
+        
+        // Code  now goes back and repeats the test with the value of age just entered
+    }
+    return 0;	// Exit code
+}