大整数加法和乘法（stl）

#include <iostream>
#include <string>
#include <deque>
#include <functional>
#include <algorithm>


using namespace std;

class MyBigNum
{
    deque<int>v;
public:
    MyBigNum(){};
    MyBigNum(string strNum)
    {
        copy(strNum.begin(),strNum.end(),back_inserter(v));
        transform(v.begin(),v.end(),v.begin(),bind2nd(minus<int>(),'0'));
    }

    deque<int>::iterator begin()
    {
        return v.begin();
    }
    deque<int>::iterator end()
    {
        return v.end();
    }
    int size()
    {
        return v.size();
    }
    back_insert_iterator<deque<int>>Back_Inserter()//这段有错误，不知道怎么改
    {
        return back_inserter(v);
    }
    void push_front(int n)
    {
        v.push_front(n);
    }
    void push_back(int n)
    {
        v.push_back(n);
    }
    void adjust()
    {
        int nSize=v.size();

        for(int i=nSize-1;i>=1;i--)
        {
            int value=v[i];
            if(value<10)
                continue;
            v[i]=value%10;
            v[i-1]=value/10;
        }
      
        int value=v[0];
        if(value>=10)
        {
            v[0]=value%10;
            value=value/10;
            while(value>0)
            {
                v.push_front(value%10);
                value/=10;
            }
        }
        nSize=v.size();
    }

    MyBigNum Add(MyBigNum &m)
    {
        MyBigNum result;
        int n=size()-m.size();
        if(n>=0)
        {
            transform(begin()+n,end(),m.begin(),result.Back_Inserter(),plus<int>());
            for(int i=n-1;i>=0;i--)
            {
                result.push_front(*(begin()+i));
            }
        }
        else
        {
            transform(begin(),end(),m.begin()-n,result.Back_Inserter(),plus<int>());
            for(int i=-n-1;i>=0;i--)
            {
                result.push_font(*(m.begin()+i));
            }
        }
        result.adjust();
        return result;
    }

    MyBigNum Multiply(MyBigNum& m)
    {
        MyBigNum mid;
        for(int i=0;i<m.size();i++)
        {
            mid=*this;
            for(int j=0;j<i;j++)
            {
                mid.push_back(0);
            }
            transform(mid.begin(),mid.end(),mid.begin(),bind2nd(multiplies<int>(),
                *(m.begin()+i)));
            result=mid.Add(result);
        }
        return result;
    }
    };
    void main()
    {
        MyBigNum m1("1234567890");
        MyBigNum m2("99999999998");
        MyBigNum result=m1.Add(m2);
        cout<<"1234567890+99999999998=";
        copy(result.begin(),result.end(),ostream_iterator<int>(cout));
        cout<<endl;

        MyBigNum m3("99");
        MyBigNum m4("99999");
        MyBigNum m5=m3.Multiply(m4);
        cout<<"99*99999=";
        copy(m5.begin(),m5.end(),ostream_iterator<int>(cout));
        cout<<endl;
    }