Swapping two numbers using Reference Parameters in C++

swap.cpp

#include <iostream>
using namespace std;
void swap(int& a, int& b) {
    a = a-b;
    b = b+a;
    a = b-a;
}
int main() {
    int a = 10;
    int b = 20;
    swap(a,b);
    cout << "a = " << a << endl;
    cout << "b = " << b << endl;
}