21、栈的应用-就近匹配

main.c

/*
就近匹配，找出不匹配的符号用箭头A标注出来
这里只写了小括号的匹配
*/


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

typedef struct MYCHAR {
    StackNode node;
    char* pAddres;
    int index;
}MyChar;

int IsLeft(char c) {
    return c == '(';
}
int IsRight(char c) {
    return c == ')';
}

MyChar* CreatMyChar(char* p, int index) {
    MyChar* mychar = (MyChar*)malloc(sizeof(MyChar));
    mychar->pAddres = p;
    mychar->index = index;

    return mychar;
}
void ShowError(char* str, int pos) {
    printf("%s\n", str);
    for (int i = 0; i < pos; i++) {
        printf(" ");
    }
    printf("A");
}

int main() {

    //char* str1 = "#include<stdio.h> int main(){int a[4][4];int (*p)[4];p=a[0];return 0;}";
    char* str = "1+2+6(desa)ads)e(rfsd)";

    //创建栈容器
    LinkStack* stack = InitStack();

    char* p = str;
    SElemType* e = (SElemType*)malloc(sizeof(SElemType));
    int index = 0;
    while (*p != '\0') {

        //如果是左括号 直接进栈
        if (IsLeft(*p)) {
            Push(stack, (StackNode*)CreatMyChar(p, index));
        }
        //如果是右括号 从栈顶弹出元素 判断是不是左括号
        if (IsRight(*p)) {
            if (StackLength(stack) > 0) {
                MyChar* mychar = (MyChar*)GetTop(stack);
                if (IsLeft(*(mychar->pAddres))) {
                    Pop(stack, e);
                    free(mychar);
                }
            }
            else {
                printf("右括号没有匹配的左括号：\n");
                ShowError(str, index);
                break;
            }

        }
        p++;
        index++;
    }

    while (StackLength(stack) > 0) {
        MyChar* mychar = (MyChar*)GetTop(stack);
        printf("左括号没有匹配的右括号：\n");
        ShowError(str, mychar->index);
        Pop(stack, e);
        free(mychar);
    }

    free(e);

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

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 void* 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，返回S的栈顶元素
void* GetTop(LinkStack *s);
//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，返回S的栈顶元素
void* GetTop(LinkStack *s) {
    if (s == NULL) {
        return NULL;
    }

    return s->top->data;
}
//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

    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

    s->count--;
    return OK;
}
//返回栈S的元素个数
Status StackLength(LinkStack *s) {

    int j = s->count;
    return j;
}

VS2015运行结果：