Passing a function as an argument to a function

In C, while calling a function to carry out a task, usually the data for the function is sent as arguments. But it is also possible to send a function itself as an argument. The following program defines two functions add( ) and sub( ) which are passed as an argument to another function.

//C program to pass function as an argument

#include<stdio.h>

int add(int,int);

int sub(int,int);

void f_calling_f(int,int,int (*)(int,int));

void main ()

{

  clrscr();

  printf("Passing function to function\n");

  f_calling_f(10,20,add);

  f_calling_f(10,20,sub);

  getch();

}

void f_calling_f(int a,int b,int (*f)(int,int))

{

   f(a,b);

}

int add(int a,int b)

{

   printf("\nThe result of addition of %d and %d is %d\t",a,b,a+b);

}

int sub(int a,int b)

{

   printf("\nThe result of subtraction of %d and %d is %d\t",a,b,a-b);

}

/*

OUTPUT

------------

Passing function to function

                                                                                

The result of addition of 10 and 20 is 30                                       

The result of subtraction of 10 and 20 is -10

*/