C++ program to swap two variable without using third variable

In this chapter of C++ program tutorial out task is: 

• Write a C++ program to swap two variables without using third variable.

C++ program to swap two variable without using third variable

Given below  are the three different methods to swap two variable without using the third variable in c++

Method 1 : 

#include<iostream>
using namespace std;
int main()
{
    int a,b,temp=0;
    cout<<"Enter the two variable"<<endl;
    cin>>a>>b;
    cout<<"Value before swapping"<<endl;
    cout<<"a = "<<a<<"\t"<<"b = "<<b<<endl;
    a = a + b;
    b = a - b;
    a = a - b;
    cout<<"Value after swapping"<<endl;
    cout<<"a = "<<a<<"\t"<<"b = "<<b<<endl;
    return 0;
}

OUTPUT :

Enter the two variable

• The execution starts from the main function (here int main()).
• Then a 4 bit each for the two integers are created (assuming the system to be 64 bit).
• Then the compiler accepts the two variable as the input.
• The total value of "a" and "b" is stored in "a" by addition.
• Then in "b" the value of orginal "b" is subtracted form "a".
• Then in "a" the value of  "a" is subtracted form the new "b" and the value get reversed.
• The program than gives the desired output and terminates in the line "return 0" returning a 0 value.

WORKING:

a = 10 and b = 20

a = a + b     ( a = 10 + 20 = 30 )

b = a - b      ( b = 30 - 20 = 10 )

a = a - b      ( a = 30 - 10 = 20 )

So, a = 20 and b = 10

You can see the above code execution and output in codeblocks IDE:

Method 2:

#include<iostream>
using namespace std;
int main()
{
    int a,b,temp=0;
    cout<<"Enter the two variable"<<endl;
    cin>>a>>b;
    cout<<"Value before swapping"<<endl;
    cout<<"a = "<<a<<"\t"<<"b = "<<b<<endl;
    a = a * b;
    b = a / b;
    a = a / b;
    cout<<"Value after swapping"<<endl;
    cout<<"a = "<<a<<"\t"<<"b = "<<b<<endl;
    return 0;
}

#include<iostream>
using namespace std;
int main()
{
    int a,b,temp=0;
    cout<<"Enter the two variable"<<endl;
    cin>>a>>b;
    cout<<"Value before swapping"<<endl;
    cout<<"a = "<<a<<"\t"<<"b = "<<b<<endl;
    a = a ^ b;
    b = a ^ b;
    a = a ^ b;
    cout<<"Value after swapping"<<endl;
    cout<<"a = "<<a<<"\t"<<"b = "<<b<<endl;
    return 0;
}

WORKING:

a = 10 (01010) and b = 20 (10100)

a = a ^ b     ( a = 01010 ^ 10100 = 11110 [30] )

b = a ^ b      ( b = 11110 ^ 10100 = 01010 [10] )

a = a ^ b      ( a = 11110 ^ 01010 = 10100 [20] )

So, a = 20 and b = 10

You can see the above code execution and output in codeblocks IDE:

Sayantan Bose
- 🔭 I’m currently working on DS Algo skills - 🌱 I’m currently learning web develeopement - 👯 I’m looking to collaborate with Oppia - 📫 Reach me at https://www.linkedin.com/in/sayantan-bose-14134a1a6/ - 😄 Pronouns: his/him