大数相乘

来源：互联网发布：网络三大奇书编辑：程序博客网时间：2024/05/21 00:56

题目：请使用代码计算1234567891011121314151617181920*2019181716151413121110987654321。

答：

#include "stdafx.h"#include <iostream>#include <string>using namespace std;int _tmain(int argc, _TCHAR* argv[]){    string strOne;    string strTwo;    cout<<"输入第一个乘数：";    cin>>strOne;    cout<<"输入第二个乘数：";    cin>>strTwo;    int lengthOne = strOne.size();    int lengthTwo = strTwo.size();    int lengthResult = lengthOne * lengthTwo;    int *result = new int[lengthResult];    memset(result, 0, lengthResult * sizeof(int));    int count = 1;    int i, j, k;    for (i = lengthTwo - 1; i >= 0; i--)    {        k = lengthResult - count;        for (j = lengthOne - 1; j >= 0; j--)        {            result[k--] += (strTwo[i] - '0') * (strOne[j] - '0');        }        count++;    }    for (i = lengthResult - 1; i > 0; i--)    {        while(result[i] >= 10)        {            result[i] -= 10;            result[i - 1]++;        }    }    for (i = 0; i < lengthResult; i++)    {        if (0 != result[i])        {            break;        }    }    cout<<strOne<<" * "<<strTwo<<" = "<<endl;    for (; i < lengthResult; i++)    {        cout<<result[i];    }    delete [] result;    cout<<endl;    return 0;}

运行界面如下：

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