Added book examples

C10/function_example.c

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+#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

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+#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
+}