C的Stack实现

参考了-http://wujie2008.javaeye.com/blog/487015的C下的Stack实现，写了一个Stack实现

 

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

typedef struct node * Elem;

struct node
{
    int data;
    Elem next;
};

typedef Elem Stack;

void init (Stack stack)
{
    Elem p = (Elem) malloc (sizeof (Elem));
    p->next = NULL;
    stack = p;
}

int top (Stack stack)
{
    Elem p = stack->next;
    if (p != NULL)
    return p->data;
    else
    return NULL;
}

int pop (Stack stack)
{
    Elem p = stack->next;
    if (p != NULL)
    {
    int data = p->data;
    stack->next = p->next;
    //free (p); 在VS2005下面 释放内存时会发生错误
    return data;
    }
    else
    return NULL;
}

void push (Stack stack, int data)
{
    Elem p = (Elem) malloc (sizeof (Elem));
    p->data = data;
    p->next =stack->next;
    stack->next = p;
}

void main (int argc, char *argv[])
{
    //Stack s; 在VS下面必须对s进行初始化，否则会出现错误
    Stack s = (Stack) malloc (sizeof (Stack));
    init (s);
    int i;
    for (i = 0; i < 10; i++)
    push (s, i);
    for (i = 0; i < 10 ;i++)
    printf ("%d\n", pop());
    free (s);
}