Swapping of two numbers in C++

#include <iostream>

using namespace std;

int main(int argc, const char * argv[]) 
{ 
    int a = 3;
    int b = 6;

    cout << "The value of a before swap is " << a << endl;
    cout << "The value of b before swap is " << b << endl;

    // Swapping of two numbers using temp variable
    int temp = a;
    a = b;
    b = temp;

    cout << "The value of a after swap is " << a << endl;
    cout << "The value of b after swap is " << b << endl;

    return 0;
}

#include <iostream>

using namespace std;

int main(int argc, const char * argv[]) 
{ 
    int a = 3;
    int b = 6;

    cout << "The value of a before swap is " << a << endl;
    cout << "The value of b before swap is " << b << endl;

    // Swapping of two numbers using arithmetic operations
    a = a + b;
    b = a - b;
    a = a - b;

    cout << "The value of a after swap is " << a << endl;
    cout << "The value of b after swap is " << b << endl;

    return 0;
}

#include <iostream>

using namespace std;

int main(int argc, const char * argv[]) 
{ 
    int a = 3;
    int b = 6;

    cout << "The value of a before swap is " << a << endl;
    cout << "The value of b before swap is " << b << endl;

    // Swapping of two numbers using arithmetic operations
    b = a + b - (a = b);

    cout << "The value of a after swap is " << a << endl;
    cout << "The value of b after swap is " << b << endl;

    return 0;
}

#include <iostream>

using namespace std;

int main(int argc, const char * argv[]) 
{ 
    int a = 3;
    int b = 6;

    cout << "The value of a before swap is " << a << endl;
    cout << "The value of b before swap is " << b << endl;

    // Swapping of two numbers 
    // using exclusive OR operation (i.e. XOR)
    a = a ^ b;
    b = a ^ b;
    a = a ^ b;

    cout << "The value of a after swap is " << a << endl;
    cout << "The value of b after swap is " << b << endl;

    return 0;
}