c++ reference!

#include <iostream>

using std::cout;

using std::endl;

void swap(int &ra, int &rb)

{

int tmp = ra;

ra = rb;

rb = tmp;

}

int main()

{

int a = 100;

int b = 200;

cout << "a : " << a << "\t" << "b : " << b << endl;

swap(a,b);

cout << "a : " << a << "\t" << "b : " << b << endl;

return 0;

}