如何删除记录[C++学生管理系统]

Question

我在做一个学生管理系统。除了Delete Student Info函数之外，所有的函数都工作得很好。在学习C++语言方面，我完全是个新手。

当我尝试使用Delete函数时，结果会是这样的，就像一个循环：

​

​

这是我的删除代码：

void student::deleted()
{
    system("cls");
    fstream file, file1;
    int found = 0;
    string snum;
    cout<<"\t\t\t\t-------------------------------------------\t\t\t"<<endl;
    cout<<"\t\t\t\t---------Delete Student Information--------\t\t\t"<<endl;
    file.open("Records.txt", ios::in);
    
    if (!file)
    {
        cout << "\n\t\t\tNo information is available.";
        file.close();
    }
    
    else
    
    {
        cout <<"\nEnter Student Number you want to remove: ";
        cin >> snum;
        file1.open("Records1.txt", ios::app | ios::out);
        file >> student_num >> name >> bday >> address >> gender >> degree >> year;
        
        while (!file.eof())
        {
            if(snum != student_num)
            {
            file1 << " " << student_num << " " << name << " " << bday << " " << address << " " << gender << " " << degree << " " << year ;
            
        } else 
        {
            found==0;
            cout <<"\n\t\t\tSuccessfully Deleted.";
        }
    }   
    file1 >> student_num >> name >> bday >>address >> gender >> degree >> year ;
        
    if (found == 0)
    {
        cout <<"\n\t\t\tStudent Number not found.";
    }
    file1.close();
    file.close();
    remove("Records.txt");
    rename("Records.txt", "NewRecords.txt");
}

除了这个删除功能之外，所有的功能都在我的程序上运行。我希望你能用我还不知道的知识来启发我。

Answer 1

基本上，您的整个while循环的结构都是错误的。试试更多像这样的东西：

void student::deleted()
{
    system("cls");

    cout<<"\t\t\t\t-------------------------------------------\t\t\t"<<endl;
    cout<<"\t\t\t\t---------Delete Student Information--------\t\t\t"<<endl;
    
    ifstream inFile("Records.txt");
    if (!inFile)
    {
        cout << "\n\t\t\tCan't open file.";
        return;
    }

    ofstream outFile("NewRecords.txt");
    if (!outFile)
    {
        cout << "\n\t\t\tCan't create new file.";
        return;
    }

    cout << "\nEnter Student Number you want to remove: ";

    string snum;
    cin >> snum;
        
    bool found = false;
    while (inFile >> student_num >> name >> bday >> address >> gender >> degree >> year)
    {
        if (snum == student_num)
        {
            found = true;
        }
        else if (!(outFile << " " << student_num << " " << name << " " << bday << " " << address << " " << gender << " " << degree << " " << year)
        {
            cout << "\n\t\t\tCan't write to new file.";
            outFile.close();
            remove("NewRecords.txt");
            return;
        }
    }   

    if (!inFile.eof())
    {
        cout << "\n\t\t\tCan't read information.";
        outFile.close();
        remove("NewRecords.txt");
        return;
    }

    outFile.close();
    inFile.close();

    if (!found)
    {
        cout <<"\n\t\t\tStudent Number not found.";
        remove("NewRecords.txt");
        return;
    }

    if (rename("Records.txt", "OldRecords.txt") != 0)
    {
        cout <<"\n\t\t\tCan't backup old file.";
        remove("NewRecords.txt");
        return;
    }

    if (rename("NewRecords.txt", "Records.txt") != 0)
    {
        cout <<"\n\t\t\tCan't rename new file.";
        rename("OldRecords.txt", "Records.txt");
        return;
    }

    remove("OldRecords.txt");

    cout <<"\n\t\t\tSuccessfully Deleted.";
}