c++大数加法【原】

/*********************************
*本例实现大整数相加
*作者：yubaolee
*日期：2010-5-30
**********************************/

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

int main()
{
   string str1;
   string str2;
   while(cin>>str1>>str2)
   {
       int nLen1, nLen2, nLen;
	   nLen1 = str1.length();
	   nLen2 = str2.length();
	   nLen = nLen1 > nLen2 ? nLen1 : nLen2;
	   
	   reverse(str1.begin(), str1.end());
	   reverse(str2.begin(), str2.end());
	   
	   //高位补零
	   if (nLen > nLen1) str1.append(nLen - nLen1, '0'); 
	   if (nLen > nLen2) str2.append(nLen - nLen2, '0');
	   
	   int temp = 0;   //进位数目
	   int i = 0;
	   string strResult;    //存储结果
	   
	   while (i < nLen)
	   {
	       if(str1[i] -0x30 + str2[i] + temp > '9')
		   {
			   strResult.append(1, str1[i] + str2[i] - '9' - 1 + temp);
			   temp = 1;
		   }
		   else
		   {
		       strResult.append(1, str1[i] + str2[i] - '0' + temp);
			   temp = 0;
		   }
		   i++;
	   }
	   
	   if(temp == 1)
	      strResult.append(1, '1');
	   reverse(strResult.begin(), strResult.end());
	   cout<<strResult<<endl;
   }
   return 0;
}