**Swapping of two numbers in c++** is c++ program to swap two numbers in c++ without using third variable

In this tutorial, we are going to learn new program which is a simple program and most commonly used in exams or in interviews that is **Swap two numbers without using third variable**.

**What is swapping:** Swapping two number means replacing the numbers.

**logic to swap two numbers without a third variable**

Swapping of two numbers in c++

For swapping number first we have 2 numbers and without using third variable we swap numbers by doing a simple mathematical operation (sum and subtract )

1. Add first and second number and store addition in the first variable.

**a = a + b**

2. Subtract first and second number and store it in the second variable.

**b = a – b**

3. Subtract first and second number and store it in the first variable.

** a = a – b**

**C++ Program to Swap 2 Numbers Without Using a Temporary Variable**

123456789101112131415161718192021222324252627 | #include <iostream>using namespace std;int main(){ int first,second ;cout<<“Enter first\n”;cin>>first;cout<<“Enter second\n”;cin>>second;cout<<“before swaping\n first = “<<first<<“\n second = “<<second<<“\n”; first = first + second; second = first – second; first = first – second;cout<<“after swaping\n first = “<<first<<“\n second = “<<second<<“\n”; return 0;} |

**Output** :

**Explanation**:

**1. First Here we initialized the first and second variable.**

first —> for storing 1st number

second –>for storing the second number

**2. Now here goes the logic(let us take first = 10 and second=20)**

first = first + second , Therefore, first =10+20 =30

second = first – second , Therefore second = 30 – 20 =10

first = first – second, Therefore first =30 – 10 = 20

**3. Now the values of first and second are 20 and 10**

**4. The values of first and second are printed.**