// by lazy_cat
#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <Windows.h>

#define IsOpt(c) (c == '+' || c == '-' || c == '*' || c == '/')

typedef struct _VAL_ITEM {
    int     nValue;
    BOOL    bAval;      // 是否有效
} VAL_ITEM, *PVAL_ITEM;

typedef struct _OPT_ITEM {
    char    cOpt;
    BOOL    bHasCal;    // 是否计算
} OPT_ITEM, *POPT_ITEM;

int GetValueIndex(PVAL_ITEM pValItem, int nOptIndex, int nMaxIndex, BOOL bIsLeft)
{
    int nLeftIndex = nOptIndex, nRightIndex = nOptIndex + 1;
    switch (bIsLeft)
    {
    case TRUE:
        while (nLeftIndex >= 0) {
            if (pValItem[nLeftIndex].bAval)
                return nLeftIndex;
            nLeftIndex--;
        }
        break;

    case FALSE:
        while (nRightIndex <= nMaxIndex) {
            if (pValItem[nRightIndex].bAval) {
                pValItem[nRightIndex].bAval = FALSE;
                return nRightIndex;
            }
            nRightIndex++;
        }
        break;
    }
    return -1;
}

int CalWithOutBracket(char *szExp)
{
    int nResult = 0;
    int nOptCount = 0;  // 运算符个数
    for (int i = 0; TRUE; i++)
    {
        if (IsOpt(szExp[i]))
            nOptCount++;
        if (!szExp[i])
            break;
    }
    POPT_ITEM pOptItem = (POPT_ITEM)malloc(sizeof(OPT_ITEM) * nOptCount);
    PVAL_ITEM pValItem = (PVAL_ITEM)malloc(sizeof(VAL_ITEM) * (nOptCount + 1));
    int nOptPos = 0, nValPos = 0;

    char szNum[16] = { 0 };
    int  nDest = 0;
    for (int i = 0; TRUE; i++)
    {
        if (szExp[i] >= '0' && szExp[i] <= '9')
            szNum[nDest++] = szExp[i];
        else 
        {
            if (nDest)
            {
                pValItem[nValPos].nValue = atoi(szNum);
                pValItem[nValPos].bAval = TRUE;
                nValPos++;
                nDest = 0;
                RtlZeroMemory(szNum, sizeof(szNum));
            }            
            if (IsOpt(szExp[i])) {
                pOptItem[nOptPos].cOpt = szExp[i];
                pOptItem[nOptPos].bHasCal = FALSE;
                nOptPos++;
            }
        }
        if (!szExp[i])
            break;
    }
    for (int i = 0; i < nOptCount; i++)
    {
        if (pOptItem[i].cOpt == '*' || pOptItem[i].cOpt == '/')
        {
            int nLeftIndex = GetValueIndex(pValItem, i, nOptCount, TRUE);
            int nRightIndex = GetValueIndex(pValItem, i, nOptCount, FALSE);
            switch (pOptItem[i].cOpt)
            {
            case '*':
                pValItem[nLeftIndex].nValue *= pValItem[nRightIndex].nValue;
                break;
            case '/':
                pValItem[nLeftIndex].nValue /= pValItem[nRightIndex].nValue;
                break;
            }
            pOptItem[i].bHasCal = TRUE;
        }
    }
    for (int i = 0; i < nOptCount; i++)
    {
        if (!pOptItem[i].bHasCal)
        {
            int nLeftIndex = GetValueIndex(pValItem, i, nOptCount, TRUE);
            int nRightIndex = GetValueIndex(pValItem, i, nOptCount, FALSE);
            switch (pOptItem[i].cOpt)
            {
            case '+':
                pValItem[nLeftIndex].nValue += pValItem[nRightIndex].nValue;
                break;
            case '-':
                pValItem[nLeftIndex].nValue -= pValItem[nRightIndex].nValue;
                break;
            }
            pOptItem[i].bHasCal = TRUE;
        }
    }
    nResult = pValItem[0].nValue;
    free(pOptItem);
    free(pValItem);
    return nResult;
}

void CalBracket(char *szExp, char cLeftBrc, char cRightBrc)
{
    char *pStart = strchr(szExp, cLeftBrc);
    while (pStart)
    {
        char *pEnd = strchr(pStart, cRightBrc);
        char szPart[64];
        RtlZeroMemory(szPart, sizeof(szPart));
        strncpy(szPart, pStart + 1, pEnd - pStart - 1);
        if (!strchr(szPart, cLeftBrc))
        {
            char szTmpExp[256] = { 0 }, szNum[16] = { 0 };
            strncpy(szTmpExp, pStart + 1, pEnd - pStart - 1);
            sprintf(szNum, "%d", CalWithOutBracket(szTmpExp));
            RtlZeroMemory(szTmpExp, sizeof(szTmpExp));
            strncpy(szTmpExp, szExp, pStart - szExp);
            strcat(szTmpExp, szNum);
            strcat(szTmpExp, pEnd + 1);
            strcpy(szExp, szTmpExp);
            pStart = strchr(szExp, cLeftBrc);
            continue;
        }
        pStart = strchr(pStart + 1, cLeftBrc);
    }    
}

void main()
{
    SetConsoleTitle(TEXT("lazy_cat"));
    char szExp[256] = { 0 };
    printf("输入要计算的表达式:");
    scanf("%[^\n]s", szExp);
    CalBracket(szExp, '(', ')');
    CalBracket(szExp, '[', ']');
    CalBracket(szExp, '{', '}');
    printf("计算结果:%d\n", CalWithOutBracket(szExp));
}