C语言数据结构之栈

#include<stdio.h>
#include<stdlib.h>
struct node
{
	int date;
	struct node *next;
};
struct stack
{
	struct node *bottom;
	struct node *top;
}s;
struct stack *creat(struct stack *s);              //创建栈
void  push(struct stack *s,int e);   //入栈
void print(struct stack *s);       //打印输出
void pop(struct stack *s);         //出栈
void length(struct stack *s);      //输出栈的长度
int main()
{
	struct stack *s;
	int e;
	s=creat(s);
	push(s,67);
	push(s,3);
    push(s,88);
    push(s,6);
    push(s,1);
    push(s,7);
    push(s,0);
    printf("初始栈元素为：");
    print(s);
    printf("\n");
    printf("\n");
    push(s,-9);
    printf("插入元素后：");
    print(s);
    printf("\n");
    printf("\n");
    pop(s);
    pop(s);
    pop(s);
    printf("删除元素后：");
    print(s);
    printf("\n");
    printf("\n");
    length(s);
	return 0;
}
struct stack *creat(struct stack *s)
{
	s=(struct stack *)malloc(sizeof(struct stack ));
	s->bottom=s->top=(struct node *)malloc(sizeof(struct node));
	s->top->next=NULL;
    s->bottom->next=NULL;
	return s;
}
void  push(struct stack *s,int e)//进栈
{
    struct node *p;
    p=(struct node *)malloc(sizeof(struct node));
	p->date=e;
	p->next=NULL;
	s->top->next=p;
	s->top=p;
}
void pop(struct stack *s)// 出栈
{
   struct node *p,*q;
   p=s->bottom;
   while(p->next!=NULL)
     {
          q=p;
          p=p->next;
          
     }
    q->next=NULL;
    s->top=q;
}
void print(struct stack *s)//打印输出
{
    struct node *p = s->bottom->next;
	while(p!=NULL)
	{
		printf("%4d",p->date);
		p=p->next;
	}
}

void length(struct stack *s)//计算长度
{
   struct node *p=s->bottom->next;
   int i=0;
   while(p!=NULL)
    {
        i++;
        p=p->next;
    }
   printf("此时栈的长度为：%4d",i);
}