Passing Pointer to a Function
A function can also be passed to another function by passing its address to that function; In simple terms, it could be achieved via pointers.
Example:
C++
// C++ program to pass function as a// pointer to any function#include <iostream>using namespace std;// Function that add two numbersint add(int x, int y) { return x + y; }// Function that multiplies two// numbersint multiply(int x, int y) { return x * y; }// Function that takes a pointer// to a functionint invoke(int x, int y, int (*func)(int, int)){ return func(x, y);}// Driver Codeint main(){ // Pass pointers to add & multiply // function as required cout << "Addition of 20 and 10 is "; cout << invoke(20, 10, &add) << '\n'; cout << "Multiplication of 20" << " and 10 is "; cout << invoke(20, 10, &multiply) << '\n'; return 0;} |
Addition of 20 and 10 is 30 Multiplication of 20 and 10 is 200
Passing a Function as a Parameter in C++
A function is a set of statements that take inputs, perform some specific computation, and produce output. The idea to use functions is to perform some commonly or repeatedly done tasks together and make a function so that instead of writing the same code again and again for different inputs.
The general form of a function is in the below format:
return_type function_name([ arg1_type arg1_name, ... ])
{
// Perform Operations
}
Passing a function as an argument is a useful concept in C++. This concept has already been used while passing a custom comparator function as an argument in std::sort() to sort a sequence of objects as per the need. In this article, we will discuss different ways to design functions that accept another function as an argument.
A function can be passed as a parameter with 3 approaches i.e.
- Passing as Pointer
- Using std::function<>
- Using Lambdas