C++ 文件操作（简易的学籍管理系统）

这是一个简易的学籍管理系统，大一时居然三个人写了一千多行......年少无知啊！欢迎摘果实！
 
  1 #include <iostream>
 #include <fstream>
 #include <string>
 #include <sstream>
 using namespace std;
 
 /*
 *信息结构
 */
 /*struct stu
 {
     string id;
     string name;
     string gender;
     int age;
     string magor;
     string prize;
 };*/
 
 bool isFind = false;//是否找到的标识
 
 void find(const char *file, const int id);
 void del(const char *file, const int id);
 void change(const char *file, const int id);
 
 void add(const char *file)
 {
     ofstream out;
     out.open(file, ios::app);
     if (!out.is_open())
     {
         cout << "文件打开失败" << endl;
         return;
     }
     else
     {
         int id, age;
         string name, major, prize, gender;
         cout << "输入学号、姓名、性别、年龄、专业、奖项：" << endl;
         cin >> id >> name >> gender >> age >> major >> prize;
         find(file, id);
         if(!isFind)
             out << id << "\n" << name << "\n" << gender << "\n" << age << "\n" << major << "\n" << prize << "\n";
         else
         {
             cout << "该学号已存在..." << endl;
             return;
         }
         cout << "添加成功" << endl;
         out.close();
     }
 }
 
 void find(const char *file, const int id)
 {
     ifstream in;
     in.open(file, ios::in | ios::binary);
     if (!in.is_open())
     {
         cout << "打开文件错误" << endl;
         return ;
     }
     while(in.peek() != EOF)
     {
         int temp;
         stringstream s;
         string line;
         getline(in, line);//读字符串
         s << line;
         s >> temp;
         if (temp == id)
         {
             isFind = true;//找到
             int age;
             string name, major, prize, gender;
             cout << "找到记录："<< endl;
             getline(in, line);//读名字
             s << line; s >> name;
             getline(in, line);//读性别
             s << line; s >> gender;
             getline(in, line);//读年龄
             s << line; s >> age;
             getline(in, line);//读专业
             s << line; s >> major;
             getline(in, line);//读奖项
             s << line; s >> prize;
 
             cout << "学号：" << temp << "  ";
             cout << "姓名：" << name << "  ";
             cout << "性别：" << gender << "  ";
             cout << "年龄：" << age << "  ";
             cout << "专业:" << major << endl;
             cout << "奖项：" << prize << endl;
         }
     }
     in.close();
 }
 
 void del(const char *file, const int id)
 {
     isFind = false;
     find(file, id);//找到要删的位置
     if(isFind)
         cout << "正在删除..." << endl;
     else
     {
         cout << "无此纪录！" << endl;
         isFind = false;
         return;
     }
     ifstream in;
     in.open(file, ios::in | ios::binary);
     if (!in.is_open())
     {
         cout << "打开文件错误" << endl;
         return;
     }
     string tempStr;
     while (in.peek() != EOF)
     {
         int temp;
         string line;
         getline(in, line);//读字符串
         stringstream s;
         s << line;
         s >> temp;
         if (temp == id)
         {
             int delLine = ;
             while (delLine--)
                 getline(in, line);
         }
         else
         {
             //getline(in, line);//读字符串
             tempStr += line;
             tempStr += "\n";
         }    
 
     }
     in.close();
     //重新写入文件
     ofstream out;
     out.open(file, ios::out);
     if (!out.is_open())
     {
         cout << "打开文件错误，删除失败！" << endl;
         return;
     }
     else
     {
         out << tempStr;//重新写入
         cout << "删除完成！" << endl;
     }
     out.close();
 }
 
 void change(const char *file, const int id)
 {
     isFind = false;
     find(file, id);//找到要改的目标
     if (isFind)
     {
         int age;
         string name, major, prize, gender;
         cout << "输入新的姓名、性别、年龄、专业、奖项：" << endl;
         cin >> name >> gender >> age >> major >> prize;
         ifstream in;
         in.open(file, ios::in | ios::binary);
         if (!in.is_open())
         {
             cout << "文件打开失败！" << endl;
             return;
         }
         string tempStr;
         while (in.peek() != EOF)
         {
             int temp;
             string line;
             stringstream s;
             getline(in, line);
             s << line;
             s >> temp;
             if (temp == id)
             {
                 tempStr += to_string(id) + "\n";
                 tempStr += name + "\n";
                 tempStr += gender + "\n";
                 tempStr += to_string(age) + "\n";
                 tempStr += major + "\n";
                 tempStr += prize + "\n";//加入新信息
                 int delLine = ;
                 while (delLine--)
                     getline(in, line);//跳过旧信息
             }
             else
             {
                 tempStr += line;
                 tempStr += "\n";
             }
         }
         in.close();//别忘记
 
         //重新写入文件
         ofstream out;
         out.open(file, ios::out);
         if (!out.is_open())
         {
             cout << "打开文件错误，删除失败！" << endl;
             return;
         }
         else
         {
             out << tempStr;//重新写入
             cout << "修改完成！" << endl;
         }
         out.close();
     }
 }
 
 int main()
 {
     const char *file = "D:\\homework\\DB\\test.txt";//文件地址
     while (true)
     {
         int ans;
         cout << "--------------------------------" << endl;
         cout << "-->       1.插入信息         <--" << endl;
         cout << "-->       2.查找信息         <--" << endl;
         cout << "-->       3.删除信息         <--" << endl;
         cout << "-->       4.修改信息         <--" << endl;
         cout << "-->       0.退出Demo         <--" << endl;
         cout << "--------------------------------" << endl;
         cout << "输入指令~$ ";
         cin >> ans;
         switch (ans)
         {
         case :
         {
             cout << "已退出！" << endl;
             return ;
         }
             break;
         case :
         {
             add(file);
         }
             break;
         case :
         {
             cout << "输入要查找的学号：";
             int id;
             cin >> id;
             find(file, id);
         }
         break;
         case :
         {
             cout << "输入要删除的学生学号：";
             int id;
             cin >> id;
             del(file, id);
         }
         break;
         case :
         {
             cout << "输入要修改的学生学号：";
             int id;
             cin >> id;
             change(file, id);
         }
         default:
         {
             cout << "输入有误！" << endl;
         }
             break;
         }
     }
 
     return ;
 }