Added book examples

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
+}