程序没错误，但是运行有错误，从第2个开始，请问怎么更改

#include<fstream>
#include<iostream>
#include<string>
#include<cstdlib>
using namespace std;
//定义时间日期类表示学生的出生年月日
class Date
{
public:
    void SetDate () //设置年月日
    {
        
cout<<"请输入图书出版年"<<endl;
cin>>Year;
cout<<"请输入出版月"<<endl;
cin>>Month;
cout<<"请输入出版日"<<endl;
cin>>Day;
    }
int GetYear() //获取年份
{
    return Year;
}
int GetMonth () //获取月份
{
    return Month;
}
int GetDay() //获取日
{
    return Day ;
}
private:
    int Year;
    int Month;
    int Day;
};
//定义学生类，包含学生的学号、姓名、出生年月日
class Book
{
public:
    void SetStuValues(Date &birthday) //设置学生的学号、姓名
{
    cout<<"请输入图书编号"<<endl;
    cin>>num;
    cout<<"请输入书籍名称"<<endl;
    cin>>name;
    birthday. SetDate ();
}
void SetNum() //设置学生的学号
    {
        cin>>num;
    }
int GetNum () //获得学生的学号
{
    return num;
}

void SetName() //设置学生的姓名
    {
        cin>>name;
    }
string GetName () //获得学生的姓名
{
return name;
}
void SetBirthday (Date &birthday) //设置年月日
    {
          birthday.SetDate();
    }
int GetBirYear (Date &birthday) //获得年
{
return birthday.GetYear();
}
int GetBirMonth (Date &birthday) //获得月
    {
         return birthday. GetMonth();
    }
int GetBirDay (Date &birthday) //获得日
{
return birthday. GetDay ();
}

//1. 输入学生记录
void InputBook (Date &birthday)
    {
        char choice;
        cout<<"输入书籍记录"<<endl;
        ofstream outfile ("book.txt",ios::app); //打开文件
        if (! outfile)
{
    cout<<"文件打开失败"<<endl;
}
SetStuValues(birthday);
outfile<<"GetNum()"<<" "<<"GetName()" <<" "<<"birthday.GetYear()" <<" "<<"birthday. GetMonth()"<<" "<<"birthday. GetDay()"<<endl;
outfile.close();
cout<<"是否继续输入书籍信息 输入y(继续)或者n(停止)";
cin>>choice;
if (choice=='y')
{
    InputBook(birthday);
}
outfile. close ();
system("pause");
    }
//2. 浏览全部学生记录
void OutputBook ()
{
    int count =0;
    int year;
    int month;
    int day;
    ifstream infile ("student.txt",ios::in);
    if (infile)
        {
            cout<<"文件打开成功"<<endl;
        }
    else
    {
        cout<<"文件打开失败"<<endl;
    }
while (! infile.eof ())
    {
        infile>>num>>name>>year>>month>>day;
        cout<<num<<" "<<name<<" "<<year<<" "<<month<<" "<<day<<endl;
            infile.close ();
        if (infile. peek ()=='\n') break;
}
    infile.close ();
system (" pause" );
}
//3.按学号查找学生记录
void FindByNum()
{
    int count =0;
    int year;
    int month;
    int day;
    int findnum;
    bool find = false;
    cout<<"请输入要查找的书籍编号";
    cin>>findnum;
    ifstream infile ("book.txt", ios::in);
if (! infile)
{
    cout<<"文件打开失败"<<endl;
}
    while (! infile. eof ())
    {
        infile>>num>>name>>year>>month>>day;
    if (num ==findnum)
        {
        cout<<num<<" "<<name<<" "<<year<<" "<<month<<" "<<day<<endl;
      find = true;
    }
infile.get ();
if (infile.peek()=='\n') break;
}
if (! find)
{
    cout<<"找不到这本书"<<endl;
}
infile. close ();
system(" pause" );
}
//4. 按学号删除学生记录
void DeleteByNum()
{
    int count=0;
    int year;
    int month;
    int day;
    int findnum;
    bool find = false;
    cout<<"请输入要删除的书籍编号";
    cin>>findnum;
    ifstream infile ("book. txt", ios::in);
if (! infile)
{
    cout<<"文件打开失败"<<endl;
}
ofstream outfile ("bookcopy. txt", ios::app);//打开文件
if (! outfile) 
{
    cout<<"文件打开失败"<<endl;
    exit (0);
}
while (! infile.eof() )
{
    infile>>num>>name>>year>>month>>day;
    if (num != findnum)
    {
        outfile <<num<<" "<<name<<" "<<year<<" "<<month<<" "<<day<<endl; 
    }
    else
    {
        cout<<num<<" "<<name<<" "<<year<<" "<<month<<" "<<day<<endl;
        find = true;
        cout<<"已经删除该书籍"<<endl;
    }
            infile. get ();
        if (infile. peek ()=='\n') break;
}
        if (! find)
        {
            cout<<"找不到这本书"<<endl;

        }
        infile.close();
    outfile. close ();
    remove ("book. txt"); //删除文件
    rename ("bookcopy.txt","student.txt");
}

//5.按学号修改学生的姓名
void AlterNameByNum()
{
    int count=0;
    int year;
int month;
int day;
int findnum;
string altername;
bool find = false;
cout<<"请输入要修改书籍的编号";
cin>>findnum;
cout<<"请输入要修改书籍的名称";
cin>>altername;
ifstream infile ("book. txt",ios::in);
if (! infile)
    {
        cout<<"文件打开失败"<<endl;
    }
ofstream outfile ("bookcopy.txt", ios::app); //打开文件
if(! outfile)
    {
        cout<<"文件打开失败"<<endl;
        exit (0);
    }
while (! infile.eof ())
    {
        infile>>num>>name>>year>>month>>day;    
        if (num !=findnum)
        {
            outfile <<num<<" "<<name<<" "<<year<<" "<<month<<" "<<day<<endl;
        }
        else
        {
            outfile <<num<<" "<<name<<" "<<year<<" " <<month<<" "<<day<<endl;
            find =true;
                cout<<"已修改书籍名称"<<endl;
        }
    infile.get ();
if (infile.peek()=='\n')break;
}
if (! find)
    {
        cout<<"找不到这本书"<<endl;
    }
        infile. close ();
        outfile.close ();
    remove ("book. txt"); //删除文件
    rename ("bookcopy.txt","book.txt");
}
private:
    int num;
    string name;
    Date birthday;
};
void MainShow ()
{
    cout<<"\t\t* * *图书管理系统* * *"<<endl;
    cout<<"\t\t* * *1.输入图书* * *"<<endl;
    cout<<"\t\t* * *2.浏览全部图书记录* * *"<<endl;
    cout<<"\t\t* * *3.按编号查找图书记录* * *"<<endl;
    cout<<"\t\t* * *4.按编号删除图书记录* * *"<<endl;
    cout<<"\t\t* * *5.按编号修改图书的名称* * *"<<endl;
    cout<<"\t\t* * *6.图书出版年* * *"<<endl;
    cout<<"\t\t* * *7.退出系统* * *"<<endl;
}
void Select ()
{
    int num;
    Date stp;
    Book stu;
    Date birthday;
    cout<<"请选择功能"<<endl;
    cin>>num;
    switch(num)
    {
       case 1:
    stu. InputBook (birthday);
    MainShow();
    Select ();
    break;
       case 2:
    stu. OutputBook();
    MainShow ();
    Select ();
    break;
       case 3:    
    stu. FindByNum();
    MainShow();
    Select ();
    break;
       case 4:
    stu. DeleteByNum ();
    MainShow();
    Select ();
    break;
       case 5:
    stu. AlterNameByNum();
    MainShow();
    Select();
    break;
        case 6:
    stp.SetDate();
    MainShow();
    Select();
    break;
       case 7:
    cout<<"系统结束，谢谢再见"<<endl;
    exit (0);
    break;
    }
}
int main ()
{
    MainShow();
    Select ();
    return 0;
}

126行不应该close文件啊。才读一行就close啊