关于#c++#的问题，请各位专家解答！

Question

```

#include
#include
#include
#include
#include
using namespace std;
class Date
{
public:
void SetDate()
{
cout << "请输入年份：";
cin >> year;
cout << "请输入月份：";
cin >> month;
cout << "请输入日期：";
cin >> day;
}
int GetYear() { return year; }
int GetMonth() { return month; }
int GetDay() { return day; }
private:
int year;
int month;
int day;
};
class Student
{
public:
void InputStudent(Date &birthday)
{
ofstream outfile("student.txt", ios::app);
cout << "请输入学号：";
cin >> num;
cout << "请输入姓名：";
cin >> name;
birthday.SetDate();
cout << "请输入性别：";
cin >> gender;
cout << "请输入三门课成绩：";
cin >> score1 >> score2 >> score3;
double average = (score1 + score2 + score3) / 3.0;
int max_score = max({score1, score2, score3});
int min_score = min({score1, score2, score3});
outfile << num << " " << name << " " << birthday.GetYear() << " " << birthday.GetMonth() << " " << birthday.GetDay()
<< " " << gender << " " << score1 << " " << score2 << " " << score3 << " " << average << " " << max_score << " " << min_score << endl;
cout << "学生信息录入成功！" << endl;
outfile.close();
}
void DisplayAllStudents()
{
ifstream infile("student.txt");
string line;
while (getline(infile, line))
{
cout << line << endl;
}
infile.close();
}
void FindStudentByNum(int findnum)
{
ifstream infile("student.txt");
int num;
string line;
bool found = false;
while (infile >> num)
{
if (num == findnum)
{
getline(infile, line);
cout << num << " " << line << endl;
found = true;
break;
}
getline(infile, line);
}
infile.close();
if (!found)
{
cout << "未找到学号为 " << findnum << " 的学生" << endl;
}
}
void AlterDateByNum(int findnum)
{
// 实现修改日期的方法
// 省略具体实现代码
fstream file("student.txt");
ofstream temp("temp.txt");
int num;
string name, gender, line;
int year, month, day, score1, score2, score3;
double average;
bool found = false;
while (file >> num >> name >> year >> month >> day >> gender >> score1 >> score2 >> score3 >> average)
{
if (num == findnum)
{
Date newDate;
newDate.SetDate();
temp << num << " " << name << " " << newDate.GetYear() << " " << newDate.GetMonth() << " " << newDate.GetDay()
<< " " << gender << " " << score1 << " " << score2 << " " << score3 << " " << average << endl;
found = true;
cout << "已成功修改学号为 " << num << " 的学生的出生日期！" << endl;
}
else
{
temp << num << " " << name << " " << year << " " << month << " " << day << " " << gender << " "
<< score1 << " " << score2 << " " << score3 << " " << average << endl;
}
}
file.close();
temp.close();
remove("student.txt");
rename("temp.txt", "student.txt");
if (!found)
{
cout << "未找到学号为 " << findnum << " 的学生" << endl;
}
}
void AlterScoreByNum(int findnum)
{
// 实现修改成绩的方法
// 省略具体实现代码
fstream file("student.txt");
ofstream temp("temp.txt");
int num;
string name, gender, line;
int year, month, day, score1, score2, score3;
double average;
bool found = false;
while (file >> num >> name >> year >> month >> day >> gender >> score1 >> score2 >> score3 >> average)
{
if (num == findnum)
{
int newScore1, newScore2, newScore3;
cout << "请输入新的三门课成绩: ";
cin >> newScore1 >> newScore2 >> newScore3;
double newAverage = (newScore1 + newScore2 + newScore3) / 3.0;
int newMax = max({newScore1, newScore2, newScore3});
int newMin = min({newScore1, newScore2, newScore3});
temp << num << " " << name << " " << year << " " << month << " " << day << " " << gender << " "
<< newScore1 << " " << newScore2 << " " << newScore3 << " " << newAverage << " " << newMax << " " << newMin << endl;
found = true;
cout << "已成功修改学号为 " << num << " 的学生成绩！" << endl;
}
else
{
temp << num << " " << name << " " << year << " " << month << " " << day << " " << gender << " "
<< score1 << " " << score2 << " " << score3 << " " << average << endl;
}
}
file.close();
temp.close();
remove("student.txt");
rename("temp.txt", "student.txt");
if (!found)
{
cout << "未找到学号为 " << findnum << " 的学生" << endl;
}
}
private:
int num;
string name;
string gender;
int score1, score2, score3;
};
int main()
{
Student stu;
Date birthday;
int findnum;
int choice;
while (true)
{
cout << "***欢迎进入学生管理系统***" << endl;
cout << "1. 录入学生信息" << endl;
cout << "2. 浏览全部学生记录" << endl;
cout << "3. 按学号查找学生记录" << endl;
cout << "4. 按学号修改出生日期" << endl;
cout << "5. 按学号修改学生成绩" << endl;
cout << "6. 退出系统" << endl;
cout << "请选择功能：";
cin >> choice;
switch (choice)
{
case 1:
stu.InputStudent(birthday);
break;
case 2:
stu.DisplayAllStudents();
break;
case 3:
cout << "请输入要查找的学生学号：";
cin >> findnum;
stu.FindStudentByNum(findnum);
break;
case 4:
cout << "请输入要修改日期的学生学号：";
cin >> findnum;
stu.AlterDateByNum(findnum);
break;
case 5:
cout << "请输入要修改成绩的学生学号：";
cin >> findnum;
stu.AlterScoreByNum(findnum);
break;
case 6:
cout << "感谢使用，再见！" << endl;
return 0;
default:
cout << "无效的选项，请重新选择。" << endl;
break;
}
}
return 0;
}

```在现有的代码里面添加一个按学号删除学生记录的功能

Answer 1

以下内容由CHATGPT及阿里嘎多学长共同生成、有用望采纳：

---

很高兴帮助你添加按学号删除学生记录的功能到你的C++学生管理系统中。下面是你需要添加的代码和步骤：

1. 在主菜单中添加删除功能的选项： 修改 main 函数中的 switch 语句，添加一个新的 case 来处理删除操作。

case 7:
    cout << "请输入要删除的学生学号：";
    cin >> findnum;
    if (stu.DeleteStudentByNum(findnum)) {
        cout << "学生记录删除成功！" << endl;
    } else {
        cout << "未找到学号为 " << findnum << " 的学生记录" << endl;
    }
    break;

1. 实现删除功能的逻辑： 在 Student 类中添加一个新的成员函数 DeleteStudentByNum，实现删除逻辑。

bool Student::DeleteStudentByNum(int findnum) {
    ifstream file("student.txt");
    ofstream temp("temp.txt");
    string line;
    int num;
    bool found = false;

    // 读取原始文件，并将不匹配的记录写入临时文件
    while (file >> num) {
        if (num != findnum) {
            // 写入不匹配的记录
            temp << num;
            while (file.peek() != '\n' && !file.eof()) {
                temp << file.get();
            }
            temp << endl;
        } else {
            // 找到要删除的记录，设置found标志
            found = true;
            // 跳过当前记录的剩余部分
            while (file.peek() != '\n' && !file.eof()) {
                file.get();
            }
        }
    }

    file.close();
    temp.close();

    // 删除原始文件，并将临时文件重命名为原始文件名
    remove("student.txt");
    rename("temp.txt", "student.txt");

    return found;
}

1. 更新文件内容： 在上面的 DeleteStudentByNum 函数中，我们使用了一个临时文件 temp.txt 来存储不包含要删除记录的新文件内容。当读取到要删除的记录时，我们跳过它，不将其写入临时文件。然后，我们删除原始文件 student.txt 并将 temp.txt 重命名为 student.txt。

2. 向用户反馈操作结果： 在 DeleteStudentByNum 函数的最后，我们返回一个布尔值，表示是否找到了要删除的学生记录。在 main 函数中，我们根据这个返回值来向用户反馈操作结果。

请注意，这段代码假设你的学生记录文件 student.txt 是按照一定的格式存储的，并且每条记录都是以学号开始的。如果文件格式不同，你可能需要对代码进行相应的调整。希望这能帮助你完成你的学生管理系统的新增功能！