pku1028.cpp

这是ACM 方面的资料 是PKU的 北京大学的出来的

#include <stdio.h>
#include <string.h>

char name[1000][80];
int f[1000], b[1000];
int ftop, btop, vid, cur;

void out(int x)
{
	printf("%s\n", name[x]);
}

void init()
{
	vid = 1;
	cur = 0;
	strcpy(name[0], "http://www.acm.org/");
	btop = 0;
	ftop = 0;
}

void Visit()
{
	scanf("%s", name[vid]);
	ftop = 0;
	b[++btop] = cur;
	cur = vid;
	out(cur);
	vid++;
}

void Back()
{
	if (btop <= 0)
	{
		printf("Ignored\n");
		return;
	}
	
	f[++ftop] = cur;
	cur = b[btop];
	out(cur);
	btop--;
}

void Forward()
{
	if (ftop <= 0)
	{
		printf("Ignored\n");
		return;
	}
	b[++btop] = cur;
	cur = f[ftop];
	out(cur);
	ftop--;
}

int main()
{
	char s[10];
	int i = 0;

	init();
	while (1)
	{
		scanf("%s", s);
		if (s[0] == 'V')
			Visit();
		else if (s[0] == 'B')
			Back();
		else if (s[0] == 'F')
			Forward();
		else
			break;
	}
	
	return 0;
}