C Function Pointers Example

callback.c

#include <stdio.h>

int add(int, int);
int substract(int, int);


int perform(int (*doMath)(int, int), int a, int b) {
  return doMath(a, b);
}

void main (int argc, char *argv[]) {
  int (*doMath)(int, int);
  int var = 1;

  if(var)
   printf("%d \n", perform(add, 1, 2));
  else
   printf("%d \n", perform(substract, 1, 2));

}

int add(int a, int b) {
  return a + b;
}

int substract(int a, int b) {
  return a - b;
}