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 = 5;
            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 = 5;
                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 0:
        {
            cout << "已退出！" << endl;
            return 0;
        }
            break;
        case 1:
        {
            add(file);
        }
            break;
        case 2:
        {
            cout << "输入要查找的学号：";
            int id;
            cin >> id;
            find(file, id);
        }
        break;
        case 3:
        {
            cout << "输入要删除的学生学号：";
            int id;
            cin >> id;
            del(file, id);
        }
        break;
        case 4:
        {
            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 0;
}