How to swap two numbers using pointers in C++

In this tutorial, we are going to learn how to swap two numbers in C++ using pointers.

Before we understand the implementation let’s see what are pointers and its example along with the syntax.  We know that pointers work as a variable whose value defines the address of another variable. For example – An integer variable will always store an integer value but an integer pointer will store the address of the integer variable.

Syntax: data_type*var_name.

Implementation Algorithm

First, we will enter two user numbers and store their values in x and y. Next, we will be declaring three-pointers to store address i.e. num_1,num_2, and temp. Then we will implement a swapping procedure that goes like this.

• Set value of num_1 to temp.
• Set value of num_2 to num_1.
• Set temp value to num_2.

Now swapped numbers will be displayed using pointers num_1 and num_2.

Follow the comments in the code for better understanding.

C++ code: Swap two numbers using pointers

#include <iostream>

using namespace std;

int main()

{   int x,y;  // Input any two numbers from the user.

cout << "Enter the numbers:\n"; 

cin>>x>>y;

int *num_1,*num_2,temp; //Declaring pointers

num_1=&x;  // Declaring address 

num_2=&y; 

temp=*num_1; //Swap procedure starts

*num_1=*num_2;

*num_2=temp;

cout<<"Numbers after swapping:";   //Numbers will be displayed after swap

cout<<"\nfirst number="<<x;        //First number after swap

cout<<"\nsecond number="<<y;       // Second number after swap

return 0;

}

 

Input:

Enter the numbers:

24

58

Output:

Numbers after swapping:

first number=58
second number=24