关于文件输入流的一道题目

类的定义:
class DonativeInfo{
    friend ifstream& operator >>(ifstream& in, DonativeInfo& di){
        getline(in, di.m_name);

        string tStr;
        getline(in, tStr);
        di.m_num = atoi(tStr.c_str());

        return in;
    }
    
public:
    int    GetNum()const  {return m_num;}
    string GetName()const {return m_name;}

private:
    string  m_name;
    int     m_num;
};

所需头文件:
#include <iostream>
#include <fstream>
#include <string>

命名空间:
std

主程序:

int main(){
    ifstream fin("in.txt");
    
    int totalNum;
    string tStr;
    getline(fin, tStr);

    totalNum = atoi(tStr.c_str());

    DonativeInfo *pDI = new DonativeInfo[totalNum];
    
    for(int idx=0; idx<totalNum; ++idx)
        fin >> pDI[idx];

    cout << endl << "捐款数大于等于10000的捐款人如下:" << endl << endl;
         cout << "姓名" << "\t\t\t" << "数目" << endl;
    
    for(idx=0; idx<totalNum; ++idx){
       if(pDI[idx].GetNum() >= 10000)
    cout << pDI[idx].GetName() << "\t\t" << pDI[idx].GetNum() << endl;
    }

    cout << endl;
    delete [] pDI;

    return 0;
}

atoi(tStr.c_str())
哦 原来关键是我没有考虑用atoi吧