19.链式栈

运行截图:

完整代码:

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

//定义类型
#define datatype int

//定义栈的结点
typedef struct stack
{
    datatype data;
    struct stack *pNext;
}stack, *pstack;

//入栈  从尾部入,从尾部出(也可以从头部入从头部出)
void push(pstack *phead, datatype data)
{
    //创建新的结点
    pstack p_new_node = (pstack)malloc(sizeof(stack));
    p_new_node->data = data;
    p_new_node->pNext = NULL;

    //如果结点为NULL,第一个赋值
    if (*phead == NULL)
    {
        *phead = p_new_node;
    }
    //否则循环到结点的末尾,并把结点连接上去
    else
    {
        pstack ptmp = *phead;
        while (ptmp->pNext != NULL)
        {
            ptmp = ptmp->pNext;
        }
        ptmp->pNext = p_new_node;
    }
}

//出栈
stack *pop(pstack *phead)
{
    if (*phead == NULL)
    {
        return NULL;
    }
    //如果只有一个结点
    else if ((*phead)->pNext == NULL)
    {
        //创建结点并赋值,头结点置为空
        pstack pnew = (pstack)malloc(sizeof(stack));
        pnew->data = (*phead)->data;
        pnew->pNext = NULL;
        *phead = NULL;
        return pnew;
    }
    else
    {
        //如果大于一个结点,循环到倒数第二个节点,删除后一个
        pstack ptmp = *phead;
        while (ptmp->pNext->pNext != NULL)
        {
            ptmp = ptmp->pNext;
        }
        //创建结点并赋值
        pstack pnew = (pstack)malloc(sizeof(stack));
        pnew->data = ptmp->pNext->data;
        pnew->pNext = NULL;
        //回收内存
        free(ptmp->pNext);
        ptmp->pNext = NULL;

        return pnew;
    }
}

//显示链表数据
void show(pstack phead)
{
    if (phead == NULL)
    {
        return;
    }
    else
    {
        while (phead != NULL)
        {
            printf("%4d", phead->data);
            phead = phead->pNext;
        }
        printf("
");
    }
}

void main()
{
    pstack stack1 = NULL;
    for (int i = 0; i < 10; i++)
    {
        printf("入栈         ");
        push(&stack1, i);
        show(stack1);
    }

    
    while (stack1 != NULL)
    {
        printf("出栈:        ");
        pstack p = pop(&stack1);
        show(stack1);
    }

    system("pause");
}