#include <stdio.h>
 
int sum(int x, int y)
{
   return x + y;
}
 
int product(int x, int y)
{
   return x * y;
}
 
 
int main()
{
   int a = 13;
   int b = 5;
   int result = 0;
   int (*pfun)(int, int);
 
   pfun = sum;
   result = pfun(a, b);
   printf("\npfun = sum   result = %d", result);
 
   pfun = product;
   result = pfun(a, b);
   printf("\npfun = product         result = %d", result);
 
}
//this source code is from
//http://www.java2s.com/Code/C/Function/Pointingtofunctions.htm