数据结构手把手教学——链栈

一、链栈

1、top：指向栈顶结点的指针，空栈时top = NULL。

二、用C语言实现链栈

1、构造存储结构

typedef int datatype;

typedef struct linkstack
{
     
    datatype data;
    struct linkstack *next;
}link_stack, *link_pstack;

2、初始化

初始化让top = NULL;

void init_linkstack(link_pstack *top)
{
     
    (*top) = NULL;
}

3、入栈

new->next = top;
top = new;

void push_linkstack(link_pstack *top, datatype dat)
{
     
    link_pstack new = NULL;

    new = (link_pstack)malloc(sizeof(link_stack));
    if (NULL == new)
    {
     
        perror("malloc");
        return;
    }

    new->data = dat;
    new->next = (*top);
    (*top) = new;
}

4、出栈

出栈之前需要判断栈是否为空
t = top;t
top = top->next;
top= top->next;
free(t);

(1)、判断栈是否为空

判断top是否为NULL即可

bool isempty_linkstack(link_pstack top)
{
     
    if (NULL == top)
    {
     
        return true;
    }
    else
    {
     
        return false;
    }  
}

(2)、出栈

void pop_linkstack(link_pstack *top, datatype *dat)
{
     
    link_pstack t = NULL;

    if (isempty_linkstack(*top))
    {
     
        printf("栈已空\n");
        return;
    }

    t = (*top);
    (*dat) = t->data;   //保存出栈的数据
    (*top) = (*top)->next;
    free(t);
}

5、打印

void show_linkstack(link_pstack top)
{
     
    link_pstack p = NULL;

    for (p = top; p != NULL; p = p->next)
    {
     
        printf("%d\t", p->data);
    }

    printf("\n");
}

三、练习题

用链栈实现十进制向八进制转换。例如输入123，输出0173

1、实现代码

int main(void)
{
     
    link_pstack top = NULL;
    datatype data_push = 0;
    datatype data_temp = 0;
    datatype data_pop = 0;

    init_linkstack(&top);
    printf("输入十进制数:");
    scanf("%d", &data_push);
    data_temp = data_push;

    if (data_push < 0)
    {
     
        data_push = -data_push;
    }

    while (data_push)
    {
     
        push_linkstack(&top, data_push%8);
        data_push = data_push/8;
    }

    if (data_temp < 0)
    {
     
        printf("十进制数: %d的八进制为:-0", data_temp);
    }
    else
    {
     
        printf("十进制数: %d的八进制为:0", data_temp);
    }
    
    while (!isempty_linkstack(top))
    {
     
        pop_linkstack(&top, &data_pop);
        printf("%d", data_pop);
    }
    
    printf("\n");

    return 0;
}

2、结果

四、完整代码

https://github.com/sanjaywu/DataStructure