面向对象程序设计.txt文件

Question

#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
{
cout<<"请输入出生年份"<<endl;
cin>>year;
cout<<"请输入出生月份"<<endl;
cin>>month;
cout<<"请输入出生日"<<endl;
cin>>day;
}
int GetYear() //获取年份
{
return year;
}
int GetMonth ( ) //获取月
{
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 Student
{
public:
void SetStuValues (Date &birthday) 
{
cout<<"请输入学生的学号"<<endl;
cin>>num;
cout<<"请输入学生的姓名"<<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
{
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();    
}
void InputStudent (Date &birthday)
{
char choice;
cout<<"输入学生记录"<<endl;
ofstream outfile ("student. txt", ios::app);//打开文件
if (! outfile)
{
cout<<"文件打开失败"<<endl;
exit (0);
}
SetStuValues (birthday);
outfile <<GetNum ()<<""<<GetName()<<""<<birthday.GetYear() <<""<<birthday.GetMonth () <<""<<birthday. GetDay ()<<endl;
cout<<"是否继续输入学生信息输入y(继续)或者n(停止)";
cin>>choice;
if(choice=='y')
{
InputStudent (birthday);
}
outfile.close ();
system ("pause");
}
//2.浏览全部学生记录
void OutputStudent ()
{
int count= 0;
int year;
int month;
int day;
ifstream infile ("student.txt", ios::in);
if (! infile)
{
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. get ();
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<<"请输入要查找学生的学号";
cin>>findnum;
ifstream infile ("student. 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<<"查无此人"<<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<<"请输入要删除学生的学号";    
cin>>findnum;
ifstream infile ("student.txt", ios::in);
if(! infile)
{
cout<<"文件打开失败"<<endl;
}
ofstream outfile ("studentcopy. txt", ios::app);
if(! outfile) //打开文件
{
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<<"已经删除该学生"<<endl;
}
infile.get ();
if (infile. peek ()=='\n') break;
}
if (! find)
{
cout<<"查无此人"<<endl;
}
infile.close ();
outfile.close ();
remove ("student, txt" ) ; //删除文件
rename ("studentcopy, 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<<"请输入要修改学生的学号";
cin>>findnum;
cout<<"请输入要修改学生的姓名";
cin>>altername;
ifstream infile ("student.txt", ios::in);
if(!infile)
{
cout<<"文件打开失败"<<endl;
}
ofstream outfile ("studentcopy. txt" , ios::app) ;
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<<""<<altername<<""<<year<<""<<month<<""<<day<<endl;
 find = true;
cout<<"已经修改该学生"<<endl;
}
infile. get ();
if (infile. peek () =='\n') break;
}
if(! find)
{
cout<<"查无此人"<<endl;
}
infile. close ();
outfile. close ();
remove ("student, txt" ) ; //删除文件
rename ("studentcopy, 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<<"请输入要修改学生的学号";
cin>>findnum;
cout<<"请输入要修改学生的姓名";
cin>>altername;
ifstream infile ("student.txt", ios::in);
if(!infile)
{
cout<<"文件打开失败"<<endl;
}
ofstream outfile ("studentcopy. txt" , ios::app) ;
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<<""<<altername<<""<<year<<""<<month<<""<<day<<endl;
 find = true;
cout<<"已经修改该学生"<<endl;
}
infile. get ();
if (infile. peek () =='\n') break;
}
if(! find)
{
cout<<"查无此人"<<endl;
}
infile. close ();
outfile. close ();
Select ();
break;
case 6:
cout<<"系统结束，谢谢再见"<<endl;
exit (0);
break;
}
}
int main ()
{
MainShow ();
Select ();
return 0;
}
如果把代码修改为学生的数据属性有：学号、姓名、性别.出生日期、课程成绩。先把学生的数据属性存入到student.txt文件，其中每个学生有三门课成绩，先求三门课的平均分、三门课的最高分和最低分，再存入student.txt文件。并且把代码原有的功能修改学生姓名改成修改学生的出生日期，然后学生管理系统需要实现的功能如下：
(1)浏览全部学生记录；
(2)按学号查找学生记录；
(3)按学号删除学生记录；
(4)按学号修改学生的出生日期。
(5)按学号修改学生某门课的成绩。
完整的代码，不省略

Answer 1

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在给定的代码基础上，我们需要对类进行扩展，并添加新的功能。首先，我们需要更新Date类以包含性别，然后创建一个新的Score类来存储学生的每门课程成绩。接着，我们将更新Student类并实现所需的功能。

这里是你需要的完整代码：

#include <fstream>
#include <iostream>
#include <string>
#include <cstdlib>
#include <vector>
using namespace std;

enum class Gender { Male, Female };

// 定义分数类表示学生的单科成绩
class Score {
public:
    string course;
    int grade;

    Score(string c, int g) : course(c), grade(g) {}
};

// 更新时间日期类表示学生的出生年月日和性别
class Date {
public:
    void SetDate() {
        cout << "请输入出生年份：" << endl;
        cin >> year;
        cout << "请输入出生月份：" << endl;
        cin >> month;
        cout << "请输入出生日：" << endl;
        cin >> day;
    }

    int GetYear() const {
        return year;
    }

    int GetMonth() const {
        return month;
    }

    int GetDay() const {
        return day;
    }

    void SetGender(Gender gender) {
        this->gender = gender;
    }

    Gender GetGender() const {
        return gender;
    }

private:
    int year;
    int month;
    int day;
    Gender gender;
};

// 更新学生类，包含学生的学号、姓名、出生年月日和性别，以及三门课成绩
class Student {
public:
    void SetStuValues(Date &birthday) {
        cout << "请输入学生的学号：" << endl;
        cin >> num;
        cout << "请输入学生的姓名：" << endl;
        cin >> name;
        birthday.SetDate();
        cout << "请输入学生的性别（M/F）：" << endl;
        char genderChoice;
        cin >> genderChoice;
        if (genderChoice == 'M' || genderChoice == 'm')
            birthday.SetGender(Gender::Male);
        else if (genderChoice == 'F' || genderChoice == 'f')
            birthday.SetGender(Gender::Female);
        else {
            cout << "无效的性别选择，默认为男" << endl;
            birthday.SetGender(Gender::Male);
        }
    }

    void AddScore(Score score) {
        scores.push_back(score);
    }

    double CalculateAverageGrade() const {
        double sum = 0;
        for (const auto &score : scores) {
            sum += score.grade;
        }
        return sum / scores.size();
    }

    int GetMaxGrade() const {
        int maxGrade = scores[0].grade;
        for (const auto &score : scores) {
            if (score.grade > maxGrade) {
                maxGrade = score.grade;
            }
        }
        return maxGrade;
    }

    int GetMinGrade() const {
        int minGrade = scores[0].grade;
        for (const auto &score : scores) {
            if (score.grade < minGrade) {
                minGrade = score.grade;
            }
        }
        return minGrade;
    }

    void UpdateBirthDate(Date &newDate) {
        year = newDate.GetYear();
        month = newDate.GetMonth();
        day = newDate.GetDay();
    }

    void InputStudent(Date &birthday) {
        char choice;
        cout << "输入学生记录：" << endl;
        ofstream outfile("student.txt", ios::app); // 打开文件
        if (!outfile) {
            cout << "文件打开失败" << endl;
            exit(0);
        }
        SetStuValues(birthday);
        for (const auto &score : scores) {
            outfile << num << "" << name << "" << birthday.GetYear() << ""
                    << birthday.GetMonth() << "" << birthday.GetDay() << ""
                    << score.course << "" << score.grade << endl;
        }
        outfile.close();
        cout << "是否继续输入学生信息？输入y(继续)或者n(停止)" << endl;
        cin >> choice;
        if (choice == 'y') {
            InputStudent(birthday);
        }
        system("pause");
    }

    void OutputStudent() {
        int count = 0;
        int year;
        int month;
        int day;
        ifstream infile("student.txt", ios::in);
        if (!infile) {
            cout << "文件打开失败" << endl;
        }
        while (!infile.eof()) {
            infile >> num >> name >> year >> month >> day;
            cout << num << "" << name << "" << year << "" << month << ""
                 << day << endl;
            int gradeSum = 0;
            int gradeCount = 0;
            while (!infile.eof()) {
                string course;
                int grade;
                infile >> course >> grade;
                gradeSum += grade;
                gradeCount++;
                if (infile.peek() == '\n') break;
            }
            cout << "平均分: " << gradeSum / gradeCount << ", 最高分: "
                 << GetMaxGrade() << ", 最低分: " << GetMinGrade() << endl;
            infile.get();
            if (infile.peek() == '\n') break;
        }
        infile.close();
        system("pause");
    }

    void FindByNum() {
        int count = 0;
        int year;
        int month;
        int day;
        int findnum;
        bool found = false;
        cout << "请输入要查找学生的学号：" << endl;
        cin >> findnum;
        ifstream infile("student.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;
                cout << "平均分: " << CalculateAverageGrade() << ", 最高分: "
                     << GetMaxGrade() << ", 最低分: " << GetMinGrade() << endl;
                found = true;
            }
            infile.get();
            if (infile.peek() == '\n') break;
        }
        if (!found) {
            cout << "查无此人" << endl;
        }
        infile.close();
        system("pause");
    }

    void DeleteByNum() {
        int count = 0;
        int year;
        int month;
        int day;
        int findnum;
        bool found = false;
        cout << "请输入要删除学生的学号：" << endl;
        cin >> findnum;
        ifstream infile("student.txt", ios::in);
        if (!infile) {
            cout << "文件打开失败" << endl;
        }
        ofstream outfile("studentcopy.txt", ios::app);
        if (!outfile) { // 打开文件
            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 << "";
                for (const auto &score : scores) {
                    outfile << score.course << "" << score.grade << endl;
                }
            } else {
                cout << num << "" << name << "" << year << "" << month << ""
                     << day << endl;
                found = true;
                cout << "已经删除该学生" << endl;
            }
            infile.get();
            if (infile.peek() == '\n') break;
        }
        if (!found) {
            cout << "查无此人" << endl;
        }
        infile.close();
        outfile.close();
        remove("student.txt"); // 删除文件
        rename("studentcopy.txt", "student.txt");
    }

    void UpdateGradeByNum(int targetCourse, int newGrade) {
        int findnum;
        cout << "请输入要修改成绩的学生学号：" << endl;
        cin >> findnum;
        cout << "请输入要修改的课程名称：" << endl;
        string targetCourseStr;
        cin >> targetCourseStr;
        for (auto &score : scores) {
            if (score.course == targetCourseStr) {
                score.grade = newGrade;
                cout << "已将" << targetCourseStr << "的成绩修改为" << newGrade
                     << endl;
                break;
            }
        }
        OutputStudent();
    }

private:
    int num;
    string name;
    Date birthdate;
    vector<Score> scores;
};

void MainShow() {
    cout << "欢迎使用学生管理系统" << endl;
    cout << "1. 输入学生信息" << endl;
    cout << "2. 浏览所有学生记录" << endl;
    cout << "3. 按学号查找学生记录" << endl;
    cout << "4. 按学号删除学生记录" << endl;
    cout << "5. 按学号修改学生的出生日期" << endl;
    cout << "6. 按学号修改学生某门课的成绩" << endl;
    cout << "7. 系统退出" << endl;
}

void Select() {
    int choice;
    cout << "请选择操作：" << endl;
    cin >> choice;