【数据结构】括号匹配的检验C语言

算法

算法：
-遇到普通字符忽略

• 遇到左括号入栈
• 遇到右符号 从栈中弹出栈顶符号，比配
  • 匹配成功，继续扫描
  • 匹配失败，停止，报错
    结束：
• 所有字符扫描完毕，栈为空：成功
• 匹配失败或扫描完毕，但是栈不为空：失败

代码

//
// Created by xuehu96 on 2019-08-09.
//
#include 
#include "../linkstack.h"

int isLeft(const char c)
{
    int ret = 0;
    switch(c)
    {
        case '(':
        case '<':
        case '[':
        case '{':
        case '\'':
        case '\"':
            ret = 1;
            break;
        default:
            ret = 0;
    }
    return ret;
}

int isRight(const char c)
{
    int ret = 0;
    switch(c)
    {
        case ')':
        case '>':
        case ']':
        case '}':
        case '\'':
        case '\"':
            ret = 1;
            break;
        default:
            ret = 0;
    }
    return ret;
}

int match(const char left, const char right)
{
    switch(left)
    {
        case '(':
            return (right == ')');
        case '<':
            return (right == '>');
        case '[':
            return (right == ']');
        case '{':
            return (right == '}');
        case '\'':
            return (right == '\'');
        case '\"':
            return (right == '\"');
        default:
            return 0;
    }
}

void matchErr(const char *str, int pos)
{
    printf ("Error: braces does not match at position: %d \n", pos);
    printf ("%s\n", str);
    for(int i = 0; i < pos; ++i)
    {
        printf (" ");
    }
    printf ("^\n");
}

int scanner(const char *code)
{
    int i = 0,ret = 0;

    LinkStack *stack = NULL;
    stack = LinkStack_Create ();

    while(code[i] != '\0')
    {
        if(isLeft (code[i]))
        {
            LinkStack_Push (stack, (void *) &code[i]);
        }
        if(isRight (code[i]))
        {
            if(LinkStack_Size (stack) == 0)
            {
                matchErr (code, i);
                LinkStack_Destroy (stack);
                return 0;
            }
            char *tmp = (char *) LinkStack_Pop (stack);
            if((!match (*tmp, code[i])) || (tmp == NULL))
            {
                matchErr (code, i);
                LinkStack_Destroy (stack);
                return 0;
            }
        }
        i++;
    }

    if(code[i] == '\0' && LinkStack_Size (stack) == 0)
    {
        ret = 1;
    }
    else if(LinkStack_Size (stack) != 0)
    {
        matchErr (code, i);
        ret = 0;
    }
    else
    {
        printf ("Fail match:err\n");

    }

    LinkStack_Destroy (stack);

    return ret;
}

/*算法：
 * 遇到普通字符忽略
 * 遇到左括号入栈
 * 遇到右符号 从栈中弹出栈顶符号，比配
 *      匹配成功，继续扫描
 *      匹配失败，停止，报错
 * 结束：
 *      所有字符扫描完毕，栈为空：成功
 *      匹配失败或扫描完毕，但是栈不为空：失败
 * */

int demo_matchingSymbol()
{
    //const char *code = "#include stdio.h> int main(){int a[4][4]; int (*p)4[];p = a[0]; return 0;}";
    const char *code = "typedef struct M  { int B  ;   int C;   unsigned int  ** D ; } A;L* SeqList_Create\n";
    if(scanner (code))
    {
        printf ("success\n");
    }
    return 0;
}