move exercises and lectures into subfolders

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
+}