Added book examples

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;
+}