1.The last data in display function gets printed 2 times 2.The data in delete function doesnt gets deleted and Attend2.txt file is not removed

Question

I was making student attendance program in c++ which is not giving desired output due to 2 problems

1. the display function is not working properly, the last data is displayed twice
2. the main file that is attend2.txt is not deleted

#include<iostream>
#include<fstream>
#include<stdlib.h>
#include<string>
#include<conio.h>
using namespace std;
class attend
{
    public:
    int idn;

    void getdata()
    {
        cout<<"ENTER THE ID NUMBER "<<endl;
        cin>>idn;
        ofstream outf("Attend2.txt",ios::app);
        outf<<idn<<endl;
        outf.close();
    }
    void checkdata()
    {
        int idc,k,m=0;
        cout<<"ENTER THE ID TO CHECK "<<endl;
        cin>>idc;
        ifstream fin("Attend2,txt");
        while(fin.eof()==0)
        {
            fin>>idn;
            if(idn==idc)
            m=1;
        }
        if(m==1)
            cout<<"RECORD FOUND "<<endl;
        else
            cout<<"RECORD NOT FOUND "<<endl;
    }
    void deletedata()
    {
        int idc,k;
        cout<<"ENTER THE ID TO DELETE "<<endl;
        cin>>idc;
        ifstream fin("Attend2.txt");
        while(fin.eof()==0)
        {
            fin>>idn;
            if(idc==idn)
            {
                 cout<<"INSIDE IF "<<endl;
            }
            else
            {
                 ofstream outf("Attend3.txt",ios::app);
                 outf<<idn<<endl;
                 cout<<"ELSE IS RUNNING "<<endl;

            }
       }
       remove("Attend2.txt");
       rename("Attend3.txt","Attend4.txt");
       remove("Attend4.txt");
    }
    void displaydata()
    {
        int k=0;
        ifstream fin("Attend2.txt");
        while(fin.eof()==0)
        {
            fin>>idn;
            cout<<"THE NUMBER IS      "<<idn<<endl;
            k++;
        }
        cout<<"TOTAL NUMBER OF STUDENTS ARE   "<<k<<endl;
   }
};
int main()
{

    int k=1,ch;
    attend obj;
    cout<<"******************************************************************************"<<endl;
    cout<<"                    WELCOME TO THE ATTENDANCE SHEET                           "<<endl;
    cout<<"******************************************************************************"<<endl;
    while(k==1)
    {
        system("cls");
        cout<<"******************************************************************************"<<endl;
        cout<<"                        PRESS 1 TO ADD DATA                                   "<<endl;
        cout<<"                        PRESS 2 TO CHECK THE DATA                             "<<endl;
        cout<<"                        PRESS 3 TO DELETE DATA                                "<<endl;
        cout<<"                        PRESS 4 TO DISPLAY DATA                               "<<endl;
        cout<<"                        PRESS 5 TO EXIT                                       "<<endl;
        cout<<"                        ENTER YOUR CHOICE                                     "<<endl;
        cin>>ch;
        switch(ch)
        {
             case 1:
                    obj.getdata();
                    cout<<"                   PRESS 1 TO CONTINUE                                      "<<endl;
                    cout<<"                   PRESS 2 TO EXIT                                          "<<endl; 
                    cout<<"                   ENTER YOUR CHOICE                                        "<<endl;
                    cin>>k;
                    break;
                    case 2:
                    obj.checkdata();
                    cout<<"                   PRESS 1 TO CONTINUE                                      "<<endl;
                    cout<<"                   PRESS 2 TO EXIT                                          "<<endl; 
                    cout<<"                   ENTER YOUR CHOICE                                        "<<endl;
                    cin>>k;
                    break;
        case 3:
                obj.deletedata();
                cout<<"                   PRESS 1 TO CONTINUE                                      "<<endl;
                cout<<"                   PRESS 2 TO EXIT                                          "<<endl; 
                cout<<"                   ENTER YOUR CHOICE                                        "<<endl;
                cin>>k;
                break;
        case 4:
                obj.displaydata();
                cout<<"                   PRESS 1 TO CONTINUE                                      "<<endl;
                cout<<"                   PRESS 2 TO EXIT                                          "<<endl; 
                cout<<"                   ENTER YOUR CHOICE                                        "<<endl;
                cin>>k;
                break;
            case 5:
                    exit(0);    
            default:
                    cout<<"                  WRONG CHOICE                                              "<<endl;
                    cout<<"                  PRESS 1 TO CONTINUE                                       "<<endl;
                    cout<<"                  PRESS 2 TO EXIT                                           "<<endl; 
                    cout<<"                  ENTER YOUR CHOICE                                         "<<endl;
                    cin>>k;
        }

}
}