我刚才帮你调过了。你没看清题。每个堆栈最大值为100。数组和j改为200就行.

> #include<stdio.h>
> #include<string.h>
> char str[100][70];
> static char cmd[7];//command
> static char url[70];//web page
> main()
> {
> 	int i,j;
> 	char cur[70];//current page
> 	i=-1;//-1 表示back栈空,100表示forward栈空
> 	j=100;
> 	strcpy(cur,"http://www.acm.org");
> 	scanf("%s",cmd);
> 	while(strcmp("QUIT",cmd))
> 	{
> 		if(!strcmp(cmd,"VISIT"))
> 		{
> 			scanf("%s",url);
> 			i++;
> 			strcpy(str[i],cur);
> 			strcpy(cur,url);
> 			puts(cur);
> 			j=100;
> 		}
> 		if(!strcmp(cmd,"BACK"))
> 		{
> 			if(i!=-1)
> 			{
> 			j--;
> 			strcpy(str[j],cur);
> 			strcpy(cur,str[i]);
> 			i--;
> 			puts(cur);
> 			}
> 			else
> 				puts("Ignored");
> 		}
> 		if(!strcmp(cmd,"FORWARD"))
> 		{
> 			if(j!=100)
> 			{
> 				i++;
> 				strcpy(str[i],cur);
> 				strcpy(cur,str[j]);
> 				j++;
> 				puts(cur);
> 			}
> 			else
> 				puts("Ignored");
> 		}
> 		scanf("%s",cmd);
> 	}
> }