#include <stdio.h>
#include <unistd.h>
#include <assert.h>

main()
{
	int parent[2];
	int ret = pipe(parent);
	assert(ret != -1);

	int child[2];
	ret = pipe(child);
	assert(ret != -1);
	
	int pid = fork();
	assert(pid != -1);

	if(pid != 0)
	{
		// parent
		close(parent[0]);
		close(child[1]);
		int wfd = parent[1];
		int rfd = child[0];

		printf("go\n");
		int i = 1000000;
		while(i--)
		{
			char c = 1;
			ret = write(wfd, &c, 1);
			assert(ret == 1);
			ret = read(rfd, &c, 1);
			assert(ret == 1);
		}
		printf("done\n");
	}
	else
	{
		// child
		close(parent[1]);
		close(child[0]);
		int wfd = child[1];
		int rfd = parent[0];
		int i = 1000000;
		while(i--)
		{
			char c = 1;
			ret = read(rfd, &c, 1);
			assert(ret == 1);
			ret = write(wfd, &c, 1);
			assert(ret == 1);
		}
	}
}