c++实现高精度乘法！

    用C++写了个大数相乘，下面是源码：

/* high precision mutiply */

#include<iostream>
#include<string>
#include<iomanip>
class HighMutiply{
    private:
        const int MAX;
        int *_mutiplier;
        int *_mutipliee;
        int *_result;
        int _lenlier;
        int _lenliee;
        int _lenResult;
    public:
        HighMutiply(int max=1000)
        :MAX(max),_lenliee(0),_lenlier(0),_lenResult(0)
        {
            _mutiplier = new int[MAX];
            _mutipliee = new int[MAX];
            _result = new int[MAX * MAX];
        }

//将输入字符串按4位一组转化为整型数组
        void stringToInt(char *s1,char *s2)
        {
            char temp[5];
            int len_s1= strlen(s1);
            int len_s2= strlen(s2);
            while(len_s1>4)
            {
                strncpy(temp,&s1[len_s1-4],4);
                temp[5]='\0';
                _mutiplier[_lenlier++]=atoi(temp);
                len_s1 -= 4;
                s1[len_s1]='\0';    
            }
            if(len_s1>0)
                _mutiplier[_lenlier++]=atoi(s1);
                
            while(len_s2>4)
            {
                strncpy(temp,&s2[len_s2-4],4);
                temp[5]='\0';
                _mutipliee[_lenliee++]=atoi(temp);
                len_s2 -= 4;
                s2[len_s2]='\0';    
            }
            if(len_s2>0)
                _mutipliee[_lenliee++]=atoi(s2);
        }

//计算，结果存入_result[]中
        void Calculation()
        {
            int temp,carry;
            int i,j,count;
            for(i=0;i<MAX*MAX;i++)
            {
                _result[i]=0;
            }
            for(i = 0, carry = 0; i < _lenliee; i++ )
            {
                
                for( j = 1, count = j+i-1; j <= _lenlier; j++)
                {
                    temp = _mutipliee[i] * _mutiplier[j-1] + carry + _result[count];
                    _result[count++] =  temp % 10000;
                    carry = temp / 10000;//存储进位
                }
                while( carry )
                {
                    _result[count++] += (carry % 10000);
                    carry = carry / 10000;
                }
            }
            _lenResult=count;        
        }
        void display()
        {
            int temp,j;
            cout << _mutiplier[_lenlier-1];
            for(int i = _lenlier-2; i >= 0; i--)
            {
                if(_mutiplier[i] == 0)
                {
                    cout<<"0000";
                }
                else
                {
                    for(j=4,temp=_mutiplier[i];temp;j--,temp/=10)
                    {}
                    while(--j >= 0)
                    {
                        cout<<"0";
                    }
                    cout << _mutiplier[i];
                }
            }
            cout << " * " << _mutipliee[_lenliee-1];
            
            for(int i = _lenliee-2; i >= 0; i--)
            {
                if(_mutipliee[i] == 0)
                {
                    cout<<"0000";
                }
                else
                {
                    for(j=4,temp=_mutipliee[i];temp;j--,temp/=10)
                    {}
                    while(--j >= 0)
                    cout<<"0";
                    cout << _mutipliee[i];
                }
            }
            cout << " =" << endl << _result[_lenResult-1];
            for(int i = _lenResult-2; i >= 0; i--)
            {
                if( _result[i] == 0 )
                {
                    cout<<"0000";
                }
                else
                {
                    for(j=4,temp=_result[i];temp;j--,temp/=10)
                    {}
                    while(--j >= 0)
                        cout<<"0";
                    cout << _result[i];
                }
            }
            cout<<endl;
        }
        ~HighMutiply()
        {
            delete[] _mutipliee;
            delete[] _mutiplier;
            delete[] _result;
        }
};

int main()
{
    string s1,s2;
    cin>>s1>>s2;
    int l1=s1.length();
    int l2=s2.length();
    char *c1=new char[l1];
    char *c2=new char[l2];
    strcpy(c1,s1.c_str());
    strcpy(c2,s2.c_str());
    
    HighMutiply hi;
     hi.stringToInt(c1,c2);    
    hi.Calculation();
    hi.display();
    
    delete[] c1;
    delete[] c2;
    
    return 0;
}

    本来输入字符串想使用string类，但在VC6.0中运行老出现错误，查了MSDN后，发现是VC中存在的固有错误，后来将其改为C风格的字符串了。 程序在C-Free4.0中编译通过。