Call by reference with example in C++ - Cyborg Coding

In C++, "call by reference" is a mechanism for passing arguments to a function. When a function is called using call by reference, the memory address of the argument is passed to the function, rather than the value of the variable. This means that the function operates on the original variable, rather than a copy of it.

Here is an example of a simple C++ program that demonstrates call by reference:

#include <iostream>

void increment(int &x) {

    x++;

}

int main() {

    int num = 5;

    increment(num);

    std::cout << "The value of num is: " << num << std::endl;

    return 0;

}

In this example, the main function calls the increment function with the variable num as an argument. However, this time, it uses the ampersand & operator before the variable name in the function declaration, this tells the compiler that the function is going to modify the original variable and not a copy of it. The increment function then increments the value of x by 1. Since the function was passed the memory address of the variable num rather than the value, the function operates on the original variable and the value of num is incremented to 6. As a result, the output of the program will be The value of num is: 6.

Call by reference allows the function to directly modify the original variable, it eliminates the need to return the modified value and assign it to the original variable,