#include <iostream>
using namespace std;

int main() {
	#define TRACE(arg) cout << #arg ":" << (arg) << endl;
	
	///...a simple macro that can be used like this:
	
	int a = 5;
	TRACE(a)
	a += 7;
	TRACE(a)
	TRACE(a+7)
	TRACE(17*11)
	return 0;
}