#include <iostream>
using namespace std;

_Coroutine PingPong {
	const char * name;
	const unsigned int N;
	PingPong * part;
	void main() { // ping’s starter ::main, pong’s starter ping
		for ( unsigned int i = 0; i < N; i += 1 ) {
			cout << name << endl;
			part->cycle();
		}
	}
  public:
	PingPong( const char * name, unsigned int N, PingPong & part )
		: name( name ), N( N ), part( & part ) {}
	PingPong( const char * name, unsigned int N ) : name( name ), N( N ) {}
	void partner( PingPong & part ) { PingPong::part = &part; }
	void cycle() { resume(); }
};
int main() {
	enum { N = 10 };
	PingPong ping( "ping", N ), pong( "pong", N, ping );
	ping.partner( pong );
	ping.cycle();
}

// Local Variables: //
// tab-width: 4 //
// compile-command: "u++-work -O2 -nodebug Pingpong.cc" //
// End: //