19、链式栈

Stack.h

#ifndef STACK_H
#define STACK_H

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

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

typedef int SElemType;
typedef int Status;
//初始化结构
typedef struct StackNode{
    SElemType data;
    struct StackNode* next;
}StackNode,*LinkStackPtr;

typedef struct LinkStack {
    StackNode* top;
    int count;
}LinkStack;


//初始化操作，建立一个空栈
LinkStack* InitStack();
//将栈清空
void ClearStack(LinkStack *s);
//销毁
void DestoryStack(LinkStack *s);
//若栈为空,返回TRUE，否则返回false
Status IsEmpty(LinkStack s);
//若栈存在且非空，用e返回S的栈顶元素
void GetTop(LinkStack s, SElemType *e);
//插入元素e为新的栈顶元素
Status Push(LinkStack *s, SElemType e);
//若栈不空，则删除S的栈顶元素，用e返回其值，并返回OK，否则返回ERROR
Status Pop(LinkStack *s, SElemType *e);
//返回栈S的元素个数
Status StackLength(LinkStack *s);

//打印
void PrintfStack(LinkStack *s);

#endif

Stack.c

#include"Stack.h"

//初始化操作，建立一个空栈
LinkStack* InitStack() {
    LinkStack *s = (LinkStack*)malloc(sizeof(LinkStack));
    s->count = 0;
    s->top = (StackNode*)malloc(sizeof(StackNode));
    s->top->data = NULL;
    s->top->next = NULL;
    return s;
}
//将栈清空
void ClearStack(LinkStack *s) {


}
//销毁
void DestoryStack(LinkStack *s) {
    if (s == NULL) {
        return;
    }
    LinkStackPtr p;
    p = s->top;//将栈顶结点赋值给p
    while (p != NULL) {
        LinkStackPtr pNext = p->next;
        free(p);//释放结点p
        p = pNext;
    }
    s->count = 0;
    free(s);
}
//若栈为空,返回TRUE，否则返回false
Status IsEmpty(LinkStack s) {
    if (s.top->next == NULL) {
        return TRUE;
    }
    return FALSE;
}
//若栈存在且非空，用e返回S的栈顶元素
void GetTop(LinkStack s, SElemType *e) {


}
//插入元素e为新的栈顶元素
Status Push(LinkStack *s, SElemType e) {
    LinkStackPtr a = (LinkStackPtr)malloc(sizeof(StackNode));
    a->data = e;
    a->next = s->top;//把当前的栈顶元素赋给新结点的直接后继
    s->top = a;//将新结点a赋值给栈顶指针
    s->count++;
    return OK;
}
//若栈不空，则删除S的栈顶元素，用e返回其值，并返回OK，否则返回ERROR
Status Pop(LinkStack *s, SElemType *e) {
    StackNode* p;
    if (IsEmpty(*s)) {
        return ERROR;
    }
    *e = s->top->data;
    p = s->top;//将栈顶结点赋值给p
    printf("删除前s->top：%d
", s->top->data);
    s->top = p->next;//使得栈顶指针下移一位，指向后一结点
    free(p);//释放结点p
    printf("删除后结点释放后s->top：%d
",s->top->data);
    s->count--;
    return OK;
}
//返回栈S的元素个数
Status StackLength(LinkStack *s) {
    
    int j = s->count;
    return j;
}

//打印
void PrintfStack(LinkStack *s) {
    if (s == NULL) {
        return;
    }
    LinkStackPtr pCurrent = s->top;
    for (int i = 0; i < StackLength(s);i++) {
        printf("%d ",pCurrent->data);
        pCurrent = pCurrent->next;
    }
    printf("
");
}

main.c

#define _CRT_SECURE_NO_WARNINGS

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include"Stack.h"



int main()
{
    int m[] = { 13,24,45,46,68,78,98 };
    int n = 7;
    //初始化
    LinkStack* b = InitStack();
    SElemType e;
    printf("栈的长度为：%d 
", StackLength(b));
    //入栈
    for (int i = 0; i < n; i++) {
        Push(b, m[i]);
    }
    //打印
    printf("栈的长度为：%d 
", StackLength(b));
    PrintfStack(b);

    //出栈
    Pop(b, &e);

    //打印
    printf("栈的长度为：%d 
", StackLength(b));
    PrintfStack(b);

    //释放
    DestoryStack(b);



    printf("
");
    system("pause");
    return 0;
}

VS2015运行结果：