Parameters passing - Call by adress

#include <iostream>
#include <string>
using namespace std;
void swap(int *x, int *y)
{
    int temp = *x;
    *x = *y;
    *y = temp;
}
int main()
{
    int a = 10;
    int b = 30;
    swap(&a, &b);
    cout << a << " " << b << endl;
}