#include <iostream>
using namespace std;

void tausche(int& x, int& y) {
	int hilfe = x;
	x = y;
	y = hilfe;
}
 
int main() {
	int a=4;
	int b=7;
	cout << "Vorher: a=" << a << " b=" << b << endl;
	tausche(a,b);
	cout << "Nachher: a=" << a << " b=" << b << endl;
	return 0;
}