#include <stdio.h>  

void Twice(int, int);			// prototype

int main()
{
   int x = 5, y = 8;

   printf("Initial values of variables:\n");
   printf("\tx = %d\ty = %d\n", x, y);

   printf("Calling the function Twice(x,y)\n");
   Twice(x,y);				// what will this do?
	
   printf("The new values of x and y are:\n");
   printf("\tx = %d\ty = %d\n", x, y);
   printf("Goodbye!\n");
}

void Twice(int a, int b)
// WHAT does this function do?
{
   a *= 2;
   b *= 2;
}