C++ Program to Swap 2 Numbers using Reference and Address

To write the C++ program to swap two numbers, we need to use the concept of call by reference and call by address.

Basically in the call by reference, instead of passing the value of the variable, we pass its reference to another function.

This can be done in two ways

Creating alias of the variable in another function (Can be called as call by Reference).
By passing address or reference.

Swap two Numbers by Creating Alias

#include <iostream>
using namespace std;

void swapByReference(int &m, int &n){
    int temp= m;
    m=n;
    n=temp;
}

int main()
{
    int a,b;
    cout << "Enter two numbers A & B"<< endl;
    cin >> a;
    cin >> b;
    cout << "Value of A before swapping: " << a <<endl;
    cout << "Value of B before swapping: " << b <<endl;
    swapByReference(a,b);
    cout << "---------------------Swapping--------------------------" << endl;
    cout << "Value of A after swapping: " << a <<endl;
    cout << "Value of B after swapping: " << b <<endl;
}

#include <iostream>

using namespace std;

void swapByReference(int &m, int &n){

int temp= m;

m=n;

n=temp;

}

int main()

{

int a,b;

cout << "Enter two numbers A & B"<< endl;

cin >> a;

cin >> b;

cout << "Value of A before swapping: " << a <<endl;

cout << "Value of B before swapping: " << b <<endl;

swapByReference(a,b);

cout << "---------------------Swapping--------------------------" << endl;

cout << "Value of A after swapping: " << a <<endl;

cout << "Value of B after swapping: " << b <<endl;

}

Swap two Numbers by Passing Address

In this method, we are using pointers because pointers can store the address of the variable and can be used in another function by dereferencing it.

#include <iostream>
using namespace std;

void swapUsingAddress(int *m, int *n){
    int temp= *m;
    *m=*n;
    *n=temp;
}

int main()
{
    int a,b;
    cout << "Enter two numbers A & B"<< endl; cin >> a;
    cin >> b;
    cout << "Value of A before swapping: " << a <<endl;
    cout << "Value of B before swapping: " << b <<endl;

    swapUsingAddress(&a,&b); // Passing address of a and b

    cout << "---------------------Swapping--------------------------" << endl;
    cout << "Value of A after swapping: " << a <<endl;
    cout << "Value of B after swapping: " << b <<endl;
}

#include <iostream>

using namespace std;

void swapUsingAddress(int *m, int *n){

int temp= *m;

*m=*n;

*n=temp;

}