C++ program to swap two numbers

Here are C++ programs to swap two numbers, using third variable, without using third variable, using XOR operator, using call by pointers, using call by reference, using #define and using class . Swapping simply means interchanging. For example if x=20 and y=30 than after swapping x=30 and y=20.Now there are various methods to swap two numbers.Some of them are discussed below

C++ programs to swap two numbers using temporary variable

#include<iostream>
using namespace std;
int main()
{
    int a=10,b=5,temp;
    cout<<"Before swapping a="<<a<<" b="<<b<<endl;
    temp=a;
    a=b;
    b=temp;
    cout<<"After swapping a="<<a<<" b="<<b<<endl;
    return 0;
}

C++ programs to swap two numbers using pointers

#include<iostream>
using namespace std;
int main()
{
    int a,b,*p,*q,temp;
    cout<<"Enter two numbers : ";
    cin>>a>>b;
    p=&a;
    q=&b;
    temp=*p;
    *p=*q;
    *q=temp;
    cout<<"After swapping "<<endl;
    cout<<" a1 = "<<a<<endl;
    cout<<" a2 = "<<b<<endl;
    return 0;
}

C++ programs to swap two numbers using call by pointers

#include<iostream>
using namespace std;
void swap(int *p,int *q)
{
    int temp;
    temp=*p;
    *p=*q;
    *q=temp;
}
int main()
{
    int a,b,*p,*q,temp;
    cout<<"Enter two numbers : ";
    cin>>a>>b;
    cout<<"Before swapping "<<endl;
    cout<<" a1 = "<<a<<endl;
    cout<<" a2 = "<<b<<endl;
    swap(&a,&b);
    cout<<"After swapping "<<endl;
    cout<<" a1 = "<<a<<endl;
    cout<<" a2 = "<<b<<endl;
    return 0;
}

C++ programs to swap two numbers using call by reference

#include<iostream>
using namespace std;
void value(int &x,int &y)
{
    int temp;
    temp=x,
    x=y;
    y=temp;
}
int main()
{
    int x=10,y=20;
    cout<<"Before swapping "<<endl;
    cout<<"Value of x : "<<x<<endl;
    cout<<"Value of y : "<<y<<endl;
    value(x,y);
    cout<<"After swapping "<<endl;
    cout<<"Value of x : "<<x<<endl;
    cout<<"Value of y : "<<y<<endl;
    return 0;
}

C++ programs to swap two numbers without using third variable

#include<iostream>
using namespace std;
int main()
{
    int a=10,b=5;
    cout<<"Before swapping a="<<a<<" b="<<b<<endl;
    b=a+b;
    a=b-a;
    b=b-a;
    cout<<"After swapping a="<<a<<" b="<<b<<endl;
    return 0;
}

C++ programs to swap two numbers using bitwise XOR operator

#include<iostream>
using namespace std;
int main()
{
    int a=10,b=5;
    cout<<"Before swapping a="<<a<<" b="<<b<<endl;
    b=a^b;
    a=b^a;
    b=b^a;
    cout<<"After swapping a="<<a<<" b="<<b<<endl;
    return 0;
}

C++ programs to swap two numbers without using third variable

#include<iostream>
using namespace std;
int main()
{
    int a=10,b=5;
    cout<<"Before swapping a="<<a<<" b="<<b<<endl;
    b=a*b;
    a=b/a;
    b=b/a;
    cout<<"After swapping a="<<a<<" b="<<b<<endl;
    return 0;
}

C++ programs to swap two numbers without using third variable

#include<iostream>
using namespace std;
int main()
{
    int a=10,b=5;
    cout<<"Before swapping a="<<a<<" b="<<b<<endl;
    a=a+b-(b=a);
    cout<<"After swapping a="<<a<<" b="<<b<<endl;
    return 0;
}

C++ programs to swap two numbers using #define

#include<iostream>
using namespace std;
#define swap(a,b) a^=b^=a^=b;
int main()
{
    int a=10,b=5;
    cout<<"Before swapping a="<<a<<" b="<<b<<endl;
    swap(a,b);
    cout<<"After swapping a="<<a<<" b="<<b<<endl;
    return 0;
}

C++ programs to swap two numbers using class

#include<iostream>
using namespace std;
class swp
{
private:
    int a,b,temp;
public:
    void fswap(int &a,int &b)
    {
        temp=a;
        a=b;
        b=temp;
    }
    void getdata()
    {
        cout<<"Enter the value of a : ";
        cin>>a;
        cout<<"Enter the value of b : ";
        cin>>b;
    }
    void showdata()
    {
        cout<<"Value of a : "<<a;
        cout<<endl<<"Value of b : "<<b;
    }
    void swap()
    {
        temp=a;
        a=b;
        b=temp;
    }
};
int main()
{
    swp obj;
    obj.getdata();
    cout<<"Before swapping "<<endl;
    obj.showdata();
    obj.swap();
    cout<<endl<<"After swapping "<<endl;
    obj.showdata();
    return 0;
}