C function pointer

#include <stdio.h>
/* ww w. jav a  2s  .  c  om*/
int sum(int x, int y)
{
  return x + y;
}


int product(int x, int y)
{
  return x * y;
}


int difference(int x, int y)
{
  return x - y;
}


int main(void)
{
  int a = 10;
  int b = 5; 
  int result = 0;
  int (*pfun)(int, int);              /* Function pointer declaration      */

  pfun = sum;             
  result = pfun(a, b);                /* Call sum() through pointer        */
  printf("\npfun = sum             result = %d", result);

  pfun = product;         
  result = pfun(a, b);                /* Call product() through pointer    */
  printf("\npfun = product         result = %d", result);

  pfun = difference;      
  result = pfun(a, b);                /* Call difference() through pointer */
  printf("\npfun = difference      result = %d\n", result);
  return 0;
}

#include <stdio.h>
//  w  w w.ja v  a2 s. c o  m
int any_function(int(*pfun)(int, int), int x, int y){
  return pfun(x, y);
}

int sum(int x, int y){
  return x + y;
}

int product(int x, int y){
  return x * y;
}

int difference(int x, int y){
  return x - y;
}

int main(void){
  int a = 10; 
  int b = 5;  
  int result = 0; 
  int (*pf)(int, int) = sum;          /* Pointer to sum function */

  result = any_function(pf, a, b);
  printf("\nresult = %d", result );

  result = any_function(product,a, b);
  printf("\nresult = %d", result );

  printf("\nresult = %d\n", any_function(difference, a, b));
  return 0;
}