#include <iostream>
using namespace std;

void swap(int &a, int &b);
int &max(int &a, int &b);

int main() {
	int a = 12;
	int b = 99;

	cout << a << ' ' << b << endl;	
	
	swap(a, b);

	cout << a << ' ' << b << endl;	

	max(a, b) = 100;

	cout << a << ' ' << b << endl;	

	return 0;
}

void swap(int &a, int &b) {
	int t = a;
	a = b;
	b = t;
}

int &max(int &a, int &b) {
	if (a > b) {
		return a;
	} else {
		return b;
	}
}