C++ Program for Function Pointer

A function pointer is a pointer that points to a function. This allows functions to be passed as arguments to other functions, stored in arrays, or assigned to variables. Function pointers are useful for implementing callback functions, dynamic dispatch, and more.

Here’s a complete program that demonstrates the use of function pointers in C++

#include <iostream>

using namespace std;

// Functions to be used with function pointers

int add(int a, int b) {

    return a + b;

}

int subtract(int a, int b) {

    return a – b;

}

// Function that takes a function pointer as a parameter

void performOperation(int x, int y, int (*operation)(int, int)) {

    cout << “Result: ” << operation(x, y) << endl;

}

int main() {

    // Declare function pointers

    int (*funcPtr1)(int, int) = add;

    int (*funcPtr2)(int, int) = subtract;

    // Use function pointers to call functions

    cout << “Using function pointers directly:” << endl;

    cout << “Addition: ” << funcPtr1(10, 5) << endl; // add(10, 5)

    cout << “Subtraction: ” << funcPtr2(10, 5) << endl; // subtract(10, 5)

    // Use function pointers as arguments to another function

    cout << “\nUsing function pointers as arguments:” << endl;

    performOperation(20, 10, add); // add(20, 10)

    performOperation(20, 10, subtract); // subtract(20, 10)

    return 0;

}

Explanation of the Program

1. Function Definitions

We define two functions, ‘add’ and ‘subtract’, which perform addition and subtraction, respectively.

2. Function Pointer Declaration

We declare two function pointers, ‘funcPtr1’ and ‘funcPtr2’, and assign them to the ‘add’ and ‘subtract’ functions, respectively.

3. Calling Functions via Function Pointers

We use the function pointers to call the functions ‘add’ and ‘subtract’ directly.

4. Function with Function Pointer as Parameter

The ‘performOperation’ function takes two integers and a function pointer as parameters. It calls the function pointed to by ‘operation’ and prints the result.

5. Using Function Pointers as Arguments

We pass the ‘add’ and ‘subtract’ functions as arguments to the ‘performOperation’ function, demonstrating the flexibility of function pointers.