gistfile1.cpp

#include <iostream>

using namespace std;

#if defined __unix__
#define os 1
#elif defined _WIN32
#define os 2
#elif defined __APPLE__
#define os 3
#endif

int main()
{
	if(os == 1)
	{
		cout << "Unix\n";
	}
	else if(os == 2)
	{
		cout << "Windows\n";
	}
	else if(os == 3)
	{
		cout << "Mac/iOS\n";
	}

	return 0;

}