#include<stdio.h>
#include<malloc.h>
#include<string.h>
typedef struct node
{
	char a[80];
	struct node *next;
	struct node *pre;
}Node;
Node *head,*p;
/*function poiter int (*p[21])()
  visit()
  back()
  forward()  flag
  */

				
void visit()
{
	Node *q;
	while(p->next!=NULL)
	{
		q=p->next;
		p->next=q->next;
		free(q);
	}
	q=(Node*)malloc(sizeof(Node));
	scanf("%s",q->a);
	q->pre=p;q->next=NULL;p->next=q;
	p=q;
	printf("%s\n",p->a);
}
void forward()
{
	if(p->next==NULL)
		printf("Ignored\n");
	else
	{
		p=p->next;
		printf("%s\n",p->a);
	}
}
void back()
{
	if(p->pre==NULL)
		printf("Ignored\n");
	else 
	{
		p=p->pre;
		printf("%s\n",p->a);
	}
}
void quit()
{
	Node *q;
	
		while(p->next!=NULL)
	{
		q=p->next;
		p->next=q->next;
		free(q);
	}
		
			while(p->pre!=NULL)
		{
			q=p->pre;
			p->pre=q->next;
			free(q);
		}
			free(p);
}
		
int main()
{
	void (*fp[20])();
	char word[8];
	p=(Node*)malloc(sizeof(Node));
	strcpy(p->a,"http://www.acm.org/");
	head=p;
	p->next=p->pre=NULL;
	fp['V'-'B']=visit;
	fp['F'-'B']=forward;
	fp['B'-'B']=back;
	scanf("%s",word);
	while(word[0]!='Q')
	{
		(*fp[word[0]-'B'])();
		scanf("%s",word);
	}
	quit();
	return 0;
}

• 是不是malloc用得太多了？ (1447) FinalLaugh 2004-05-24 19:19:29