上夜班研究,勿回复,谢谢.

#include <iostream>
#include <fstream>
#include<iomanip>
using namespace std;
const int n=20;
const char* file="like.txt";
struct girl
{
    char name[n];
    int age;
    double beautiful;
    double tall;
    char sex[5];
   
};
void main()
{    bool q=false;
    char x;
    long count=0;
    girl a={"林云飞",21,999.999,1.63f,"女"};
    girl b={"苍井空",28,60,1.619f,"女"};
    ofstream fcout(file,ios::binary);
    fcout.write((char*)&a,sizeof a);
    fcout.close();
    fcout.open(file,ios::in|ios::out|ios::binary);
   
    if(fcout.is_open())
    {
        fcout.seekp(sizeof a,ios::beg);
        fcout.write((char*)&b,sizeof b);
        fcout.close();
    }
    else
    {
        cout<<"打开失败!"<<endl;
      exit(EXIT_FAILURE);
    }
   
    ifstream fcin(file,ios::binary);
    if(fcin.is_open())
    {   
        fcin.seekg(0);
        cout<<fixed;
      
        while(fcin.read((char*)&a,sizeof a))
        {
            cout<<count++<<":"<<setw(10)<<a.name<<setw(10)<<a.age<<setw(10)<<a.sex<<setw(10)<<setprecision(2)<<a.tall<<setw(10)<<setprecision(4)<<a.beautiful<<endl;
        }
        if(fcin.eof())
        {
            fcin.clear();
            //fcin.close();
        }
        else
        {
            cout<<"读取失败!"<<endl;
            exit(EXIT_FAILURE);
        }
    }
    else
    {
        cout<<"打开失败!"<<endl;
      exit(EXIT_FAILURE);
    }
      while(1)
          {
      cout<<"请输入你希望改编的编号"<<endl;
         long line;
         cin>>line;
         if(line<0||line>=count)
         {
             cout<<"输入错误!"<<endl;
               exit(EXIT_FAILURE);
         }
           streampos place=line*sizeof a;
           //fcin.open(file,ios::in|ios::out|ios::binary);
          fcin.seekg(place);
          if(fcin.fail())
          {
              cout<<"读入失败"<<endl;
               exit(EXIT_FAILURE);
          }
          else
          {
              fcin.read((char*)&a,sizeof a);
             cout<<line<<":"<<setw(10)<<a.name<<setw(10)<<a.age<<setw(10)<<a.sex<<setw(10)<<setprecision(2)<<a.tall<<setw(10)<<setprecision(4)<<a.beautiful<<endl;
             fcin.clear();
             fcin.close();
          }
      
          cout<<"请输入更改的姓名: ";
              cin>>a.name;
          cout<<"请输入更改的年龄; ";
          cin>>a.age;
          cout<<"请输入更改的性别; ";
          cin>>a.sex;
          cout<<"请输入更改的身高; ";
          cin>>a.tall;
          cout<<"请输入更改的美丽程度; ";
          cin>>a.beautiful;
          cout<<"是否继续输入?是:y 否: n"<<endl;
          cin>>x;
          if(x=='n')
          {
               fcout.open(file,ios::in|ios::binary);
          fcout.seekp(place);
          if(fcout.fail())
          {
              cout<<"读取失败"<<endl;
               exit(EXIT_FAILURE);
          }
          else
          {
          fcout.write((char*)&a,sizeof a);
          fcout.close();
          }
              q=true;
          }
          else if(x=='y')
          {
              

         
          fcout.open(file,ios::in|ios::binary);
          fcout.seekp(place);
          if(fcout.fail())
          {
              cout<<"读取失败"<<endl;
               exit(EXIT_FAILURE);
          }
          else
          {
          fcout.write((char*)&a,sizeof a);
          fcout.close();
         
          }
           continue;
          }
          else
          {
              cout<<"请输入小写y或者n"<<endl;
          }
               if(q)
                   break;
          }
        
          fcin.open(file,ios::binary);
          fcin.seekg(0);
          count=0;
          while(fcin.read((char*)&a,sizeof a))
          {
                cout<<count++<<":"<<setw(10)<<a.name<<setw(10)<<a.age<<setw(10)<<a.sex<<setw(10)<<setprecision(2)<<a.tall<<setw(10)<<setprecision(4)<<a.beautiful<<endl;
          }
          fcin.clear();
          fcin.close();

         



}