数据结构 -- 栈（二）

用链表实现栈

/******************************
* 
* 用链表表示栈
*
*******************************/

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

typedef struct linkStack{
    char data;
    struct linkStack* next;
}linkStack;

linkStack* push(linkStack* stack, char a)
{
    linkStack* link = (linkStack*)malloc(sizeof(linkStack));
    link->data = a;
    link->next = stack;
    stack = link;

    return link;
}

linkStack* pop(linkStack* stack)
{
    if(stack)
    {
        linkStack* p = stack;
        stack = stack->next;
        printf("出栈元素:%c 
",p->data);
        
        if(stack)
        {
            printf("栈顶元素:%c 
",stack->data);
        }
        else
        {
            printf("栈已空 
");
        }
        free(p);
    }
    else
    {
        printf("栈内没有元素
");
        return stack;
    }

    return stack;
}

int main()
{
    linkStack* stack = NULL;
    
    stack = push(stack, 'a');
    stack = push(stack, 'b');
    stack = push(stack, 'c');
    stack = push(stack, 'd');
    stack = pop(stack);
    stack = pop(stack);
    stack = pop(stack);
    stack = pop(stack);
    stack = pop(stack);
    
    return 0;
}