c語言-c++高精度小數減法問題

c++高精度小數減法問題

程序主要要求 主程序讀入兩個字符串類型的大數(小數)，通過函數實現小數的高精度減法。求完整的代碼和注釋，比較急，謝謝

最佳回答：

你這是什麼編輯器啊。連作用域都不分，我把變量名都改了，代碼如下：

#include <iostream>
using namespace std;
#define MAX_NUMBER_LEN 1024

bool isGreaterThan(const int* pNum1, const int* pNum2)
{
    if (pNum1 == NULL || pNum2 == NULL)
    {
        cout << "您輸入的數字有誤" << endl;
        return false;
    }

    for(int nIndx = 0; nIndx < MAX_NUMBER_LEN; ++nIndx)
    {
        if (pNum1[nIndx] > pNum2[nIndx])
            return true;
    }

    return false;
}

int main()
{

    char szNum1[1024] = {0};
    char szNum2[1024] = {0};
    int arNumber1[1024] = {0};
    int arNumber2[1024] = {0};

    cout << "請輸入兩個小數(小數位數不要超過500位)，空格分隔：" << endl;

    cin >> szNum1;
    cin >> szNum2;


    // 把第一個字符串轉化成數組
    int nCount = 0;
    int nNumLen = strlen(szNum1);
    bool bFindDot = false;
    for (int nIndex = 0, pos = nIndex + 1; nIndex < nNumLen; ++nIndex)
    {
        if (szNum1[nIndex] == '.')
        {
            bFindDot = true;
        }
        else
        {
            if(szNum1[nIndex] < '0' || szNum1[nIndex] > '9')
            {
                cout << "請輸入不是正確的數字" << endl;
                return 0;
            }
            else
            {   
                arNumber1[pos] = szNum1[nIndex] - '0';
            }
            pos++;

        }

        if (!bFindDot)
            nCount++;
    }
    arNumber1[0] = nCount;




    // 把第二個字符串轉化成數組
    nCount = 0;
    nNumLen = strlen(szNum2);
    bFindDot = false;
    for (int nIndex1 = 0, pos = nIndex1 + 1; nIndex1 < nNumLen; ++nIndex1)
    {
        if (szNum2[nIndex1] == '.')
        {
            bFindDot = true;
        }
        else
        {
            if(szNum2[nIndex1] < '0' || szNum2[nIndex1] > '9')
            {
                cout << "請輸入不是正確的數字" << endl;
                break;
            }
            else
            {   
                arNumber2[pos] = szNum2[nIndex1] - '0';
            }
            pos++;

        }

        if (!bFindDot)
            nCount++;
    }
    arNumber2[0] = nCount;


    bool isGreater = isGreaterThan(arNumber1, arNumber2);
    // 比較小數前的位數
    if (arNumber1[0] != arNumber2[0])
    {

        int nshift = abs(arNumber1[0] - arNumber2[0]);
        int *pNum;
        int nTotal;

        if(isGreater)
        {
            pNum = arNumber2;
            nTotal = strstr(szNum2, ".") ? strlen(szNum2) - 1 : strlen(szNum2);
        }
        else
        {
            pNum = arNumber1;
            nTotal = strstr(szNum1, ".") ? strlen(szNum1) - 1 : strlen(szNum1);
        }

        for(int nIndex2 = nTotal; nIndex2 >= 0; --nIndex2)
        {
            pNum[nIndex2 + nshift] = pNum[nIndex2];
        }

        for(int nIndex2 = nshift; nIndex2 >= 1; --nIndex2)
        {
            pNum[nIndex2] = 0;
        }
    }

    // 做簡單減法
    int nlen1 = strstr(szNum1, ".") ? strlen(szNum1) - 1 : strlen(szNum1);
    int nlen2 = strstr(szNum2, ".") ? strlen(szNum2) - 1 : strlen(szNum2);
    int forcount= nlen1 > nlen2 ?nlen1 : nlen2;
    if (isGreater)
    {
        for (int nIndex3 = 1; nIndex3 <= forcount; nIndex3++)
        {
            arNumber1[nIndex3] = arNumber1[nIndex3] - arNumber2[nIndex3];
        }
    }
    else
    {
        for (int nIndex4 = 1; nIndex4 <= forcount; nIndex4++)
        {
            arNumber1[nIndex4] = arNumber2[nIndex4] - arNumber1[nIndex4];
        }

    }


    // 處理減法中的負數
    arNumber1[0]  = arNumber1[0] > arNumber2[0] ? arNumber1[0] : arNumber2[0];

    for ( int nIndex5 = forcount; nIndex5 > 0; --nIndex5)
    {
        if (arNumber1[nIndex5] < 0)
        {
            arNumber1[nIndex5] += 10;
            arNumber1[nIndex5 - 1] -= 1;
        }
    }


    cout << "結果為" << endl;
    if (!isGreater)
        cout << "-";


    //輸出結果
    bool zerooutpput = false;
    bool putpucount = 0;
    for( int nIndex6 = 1; nIndex6 <= forcount; nIndex6++ )
    {
        if (arNumber1[nIndex6] != 0 || nIndex6 > arNumber1[0])
        {
            zerooutpput = true;
            cout << arNumber1[nIndex6];
            putpucount++;
        }
        else if (zerooutpput)
        {
            cout << arNumber1[nIndex6];
            putpucount++;
        }

        if (nIndex6 == arNumber1[0])
        {
            if (putpucount == 0)
                cout << "0";

            if (nIndex6 != forcount)
                cout << '.';
        }
    }


    system("pause");

    return 0;
}