链栈

/*
链栈
LJK 2018-07-04
*/
#include<stdio.h>
#include<stdlib.h>

#define MAXSIZE 15
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0

typedef int SElemType;
typedef int Status;

// 链栈结点
typedef struct stackNode
{
    SElemType data;
    struct  stackNode *next;
}StackNode;

// 链栈结构
typedef struct linkStack
{
    StackNode *top;
    int count;
}LinkStack;

// 构造一个空栈
Status InitStack(LinkStack *S)
{
    S->top = NULL;
    S->count = 0;
    return OK;
}

// 插入 e 为新的栈顶元素
Status Push(LinkStack *S, SElemType e)
{
    StackNode *s = (StackNode*)malloc(sizeof(StackNode));
    s->data = e;
    s->next = S->top;
    S->top = s;
    S->count++;
    return OK;
}

// 遍历显示链栈
Status StackTraverse(LinkStack S)
{
    StackNode *p = S.top;
    while (p)
    {
        printf("%d ", p->data);
        p = p->next;
    }
    printf("
");
    return OK;
}

// 若栈不空，则删除栈顶元素，用e返回其值
Status Pop(LinkStack *s, SElemType *e)
{
    StackNode *p;
    if (s->top == NULL) return ERROR;
    *e = s->top->data;
    p = s->top;
    s->top = s->top->next;
    free(p);
    s->count--;
    return OK;
}

Status StackEmpty(LinkStack S)
{
    if (S.count == 0) return TRUE;
    else return FALSE;
}

Status GetTop(LinkStack S, SElemType *e)
{
    if (S.top == NULL) return ERROR;
    *e = S.top->data;
    return OK;
}

int StackLength(LinkStack S)
{
    return S.count;
}

// 将S设置为空栈
Status ClearStack(LinkStack *S)
{
    StackNode *p, *q;
    p = S->top;
    while (p)
    {
        q = p;
        p = p->next;
        free(q);
    }
    S->top = NULL;
    S->count = 0;
    return OK;
}

int main()
{
    LinkStack s;
    int j;
    SElemType e;

    if (InitStack(&s) == OK)
    {
        for ( j = 1; j <= 10; j++)
            Push(&s, j);
    }
    printf("Stack:");
    StackTraverse(s);

    Pop(&s, &e);
    printf("栈顶 e = %d
", e);
    printf("Stack:");
    StackTraverse(s);
    printf("
");

    printf("栈空否：%d (1:空 0:否)
", StackEmpty(s));
    printf("
");

    printf("Len(stack) = %d
", StackLength(s));
    printf("
");

    ClearStack(&s);
    printf("清空栈后：
");
    printf("栈空否：%d (1:空 0:否)
", StackEmpty(s));
    printf("Len(stack) = %d
", StackLength(s));
    printf("
");

    getchar();
    return 0;
}