c stack

用一个头链表实现栈，头指针永远指向栈顶元素

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

typedef  int ElemenType  ;

typedef struct node{
    ElemenType data;
    struct node *next;
}Linkstack;

Linkstack *top;

Linkstack *CreateStack()
{
  Linkstack *s;
  s=(Linkstack*)malloc(sizeof(struct node));
  s->next=NULL;
  return s;
}

int IsEmpty(Linkstack *s)
{
  if(s->next==NULL)
    return 0;
  else return 1;
}

void push(Linkstack *s,ElemenType item)
{
  Linkstack *n=(Linkstack*)malloc(sizeof(struct node));
  n->data=item;
  n->next=s->next;
  s->next=n;
}

ElemenType pop(Linkstack *s)
{
  if(s->next == NULL)
    return 0;
  ElemenType item=s->data;
   Linkstack *n=(Linkstack*)malloc(sizeof(struct node));
   n=s->next;
   s->next=n->next;
   item=n->data;
   free(n);
   return item;

}

void VistStack(Linkstack *s)
{
 Linkstack *p=(Linkstack*)malloc(sizeof(struct node));
 p=s->next;
  while(p->next!=NULL)
    {
      printf("%d ",p->data);
      p=p->next;
    }
  printf("%d",p->data);//打印最后一个元素
}

int main()
{
  Linkstack *q;
  q=CreateStack();
  push(q,10);
  push(q,11);
  push(q,8);
  push(q,13);
  push(q,7);
  push(q,9);
  VistStack(q);
 ElemenType z= pop(q);
 printf("\n%d\n",z);
 VistStack(q);

  return 0;
}