Add numbers using function pointer

In this tutorial we will be learning how to add the two numbers using pointer in c programming.

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How to add two numbers using function pointer ?

#include<stdio.h>

 int sum (int n1,int n2);

 int main()
 {
 int num1 = 10;
 int num2 = 20;
 int result;

 int *(*ptr)(int,int);
 ptr = &sum;
 result = (*ptr)(num1,num2);

 printf("Addition : %d",result);

 return(0);
 }

int sum (int n1,int n2)
{
return(n1 + n2);
}

Output :

Addition : 20

Explanation :

  • Write whole program using normal function call i.e sum(num1,num2);
  • After you write whole code, just erase line in which we have called function and replace that line with following line –

Step 1 : Declaring Pointer Variable

int *(*ptr)(int,int);

means –

Declare pointer variable which is capable of storing address of function which have integer as return type and which takes 2 arguments

Step 2 : Initializing function Pointer

ptr = &sum;

using above statement we will be storing address of function in function pointer

Step 3 : Calling Function

result = (*ptr)(num1,num2);

It will call function sum(num1,num2). Above statement will be elaborated as –

result = (*ptr)(num1,num2);
result = (*&sum)(num1,num2);
result = (*&sum)(num1,num2);
result = (sum)(num1,num2);
result = sum(num1,num2);