**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**

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#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.**

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