一、关键点

1.指针变量取值或赋值

指针变量取值或赋值时如果有其他一元运算符
注意加上括号

(*p)--//表示 p指针指向的地址的内容--
*p-- //表示p指针指向的地址--

二. 代码

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

#define STACK_INIT_SIZE 100
#define STACK_INCREMENT 10
#define OVERFLOW -2
#define TRUE 1
#define FALSE 0
#define ERROR 0
#define OK 1

typedef int SElemType_Sq;
typedef int Status;
typedef struct{
    SElemType_Sq *base;
    SElemType_Sq *top;
    int stacksize;
}SqStack;

void PrintElem(SElemType_Sq e);
Status InitStack_Sq(SqStack *S);
Status DestroyStack_Sq(SqStack *S);
Status ClearStack_Sq(SqStack *S);
Status StackEmpty_Sq(SqStack S);
int StackLength_Sq(SqStack S);
Status GetTop_Sq(SqStack S, SElemType_Sq *e);
Status Push_Sq(SqStack *S, SElemType_Sq e);
Status Pop_Sq(SqStack *S, SElemType_Sq *e);
Status StackTraverse_Sq(SqStack S, void(Visit)(SElemType_Sq));

void PrintElem(SElemType_Sq e){
    printf("%d ", e);
}

Status InitStack_Sq(SqStack *S){
    S->base = (SElemType_Sq *)malloc(STACK_INIT_SIZE*sizeof(SElemType_Sq));
    if(!S->base){
        exit(OVERFLOW);
    }
    S->top = S->base;
    S->stacksize = STACK_INIT_SIZE;
    return OK;
}

Status DestroyStack_Sq(SqStack *S){
    free(S->base);
    S->base = NULL;
    S->top = NULL;
    S->stacksize = 0;
    return OK;
}

Status ClearStack_Sq(SqStack *S){
    S->top = S->base;
    return OK;
}

Status StackEmpty_Sq(SqStack S){
    return S.base == S.top?TRUE:FALSE;
}

int StackLength_Sq(SqStack S){
    return S.top-S.base;
}

Status GetTop_Sq(SqStack S, SElemType_Sq *e){
    if(S.top==S.base){
        return ERROR;
    }
    *e = *(S.top-1);
    return OK;
}


Status Push_Sq(SqStack *S, SElemType_Sq e){
    if(S->top-S->base>=S->stacksize){
        SElemType_Sq *p;
        p = (SElemType_Sq*)realloc(S->base,(S->stacksize+STACK_INCREMENT)*sizeof(SElemType_Sq));
        if(!p){
            exit(OVERFLOW);
        }
        S->base = p;
        S->top = S->base+S->stacksize;
        S->stacksize+=STACK_INCREMENT;
    }
    *(S->top) = e;
    S->top++;
    return OK;
}

Status Pop_Sq(SqStack *S, SElemType_Sq *e){
    if(S->top==S->base){
        return ERROR;
    }
    S->top--;
    *e = *(S->top);
    return OK;
}

Status StackTraverse_Sq(SqStack S, void(Visit)(SElemType_Sq)){
    SElemType_Sq *p = S.top-1;
    while(p>=S.base){
        Visit(*p--);
    }
    return OK;
}
int main(){
    SqStack S;
    int i;
    SElemType_Sq e;

    printf("▼1\n▲函数 InitStack 测试...\n");            //1.函数InitStack测试
    {
        printf("初始化顺序栈 S ...\n");
        InitStack_Sq(&S);
        printf("\n");
    }
    printf("▼4\n▲函数 StackEmpty 测试...\n");           //4.函数StackEmpty测试
    {
        StackEmpty_Sq(S) ? printf(" S 为空！！\n") : printf(" S 不为空！\n");
        printf("\n");
    }

    printf("▼7\n▲函数 Push 测试...\n");                 //7.函数Push测试
    {
        for(i=1; i<=6; i++)
        {
            printf("将 \"%2d\" 压入栈 S ", 2*i);
            Push_Sq(&S, 2*i);
            printf("（累计第 %d 个元素）...\n", S.top-S.base);
        }
        printf("\n");
    }

    printf("▼9\n▲函数 StackTraverse 测试...\n");        //9.函数StackTraverse测试
    {
        printf(" S 中的元素为：S = ");
        StackTraverse_Sq(S, PrintElem);
        printf("\n\n");
    }

    printf("▼8\n▲函数 Pop 测试...\n");                  //8.函数Pop测试
    {
        Pop_Sq(&S, &e);
        printf("栈顶元素 \"%d\" 出栈...\n", e);
        printf(" S 中的元素为：S = ");
        StackTraverse_Sq(S, PrintElem);
        printf("\n\n");
    }

    printf("▼5\n▲函数 StackLength 测试...\n");          //5.函数StackLength测试
    {
        i = StackLength_Sq(S);
        printf(" S 的长度为 %d \n", i);
        printf("\n");
    }

    printf("▼6\n▲函数 GetTop 测试...\n");               //6.函数GetTop测试
    {
        GetTop_Sq(S, &e);
        printf("栈顶元素的值为 \"%d\" \n", e);
        printf("\n");
    }

    printf("▼3\n▲函数 ClearStack 测试...\n");           //3.函数ClearStack测试
    {
        printf("清空 S 前：");
        StackEmpty_Sq(S) ? printf(" S 为空！！\n") : printf(" S 不为空！\n");
        ClearStack_Sq(&S);
        printf("清空 S 后：");
        StackEmpty_Sq(S) ? printf(" S 为空！！\n") : printf(" S 不为空！\n");
        printf("\n");
    }

    printf("▼2\n▲函数 DestroyStack 测试...\n");         //2.函数DestroyStack测试
    {
        printf("销毁 S 前：");
        S.base!=NULL && S.top!=NULL ? printf(" S 存在！\n") : printf(" S 不存在！！\n");
        DestroyStack_Sq(&S);
        printf("销毁 S 后：");
        S.base!=NULL && S.top!=NULL ? printf(" S 存在！\n") : printf(" S 不存在！！\n");
        printf("\n");
    }

    return 0;
}