链栈

#include <stdio.h>
#include <stdlib.h>

struct lstack{
	char data;
	struct lstack * next;
};

struct lstack * init(){
	struct lstack * top;
	top = (struct lstack *)malloc(sizeof(struct lstack));
	top->data='0';
	top->next=NULL;
	return top;
}

int push(struct lstack * top,char data){
	struct lstack * p;
	p=(struct lstack *)malloc(sizeof(struct lstack));
	p->data=data;
	p->next=top->next;
	top->next=p;
	printf("%c入栈\n",data);
	return 0;
}

int pop(struct lstack * top){
	struct lstack * p;
	if(top->next==NULL){
		printf("栈空！删除失败！\n");
	}
	else{
		p = top->next;
		top->next=p->next;
		printf("%c出栈\n",p->data);
		free(p);
	}
	return 0;
}

int getTop(struct lstack * top){
	struct lstack * p;
	if(top->next==NULL){
		printf("栈空！无栈顶元素！\n");
	}
	else{
		p=top->next;
		printf("当前栈顶元素：%c\n",p->data);
	}
	return 0;
}

int getLength(struct lstack * top){
	struct lstack * p;
	p=top->next;
	int len=0;
	while(p!=NULL){
		len++;
		p=p->next;
	}
	printf("当前栈的长度为：%d\n",len);
	return 0;
}

void display(struct lstack * top){
	struct lstack * p;
	if(top->next==NULL){
		printf("栈空！无元素！\n");
	}
	else{
		p=top->next;
		printf("打印当前栈：");
		while(p!=NULL){
			printf("%c ",p->data);
			p=p->next;
		}
		printf("\n");
	}
}

int main(){
	struct lstack * s;
	s=init();
	push(s,'a');
	push(s,'b');
	push(s,'c');
	getLength(s);
	display(s);
	pop(s);
	pop(s);
	pop(s);
	pop(s);
	getLength(s);
	display(s);
	getTop(s); 
	return 0;
}