Rename Problem...

[captain fantastic]

Hi! Look At this code:

#include <iostream>
#include <conio.h>
#include <cstdlib>
#include <cmath>
#include <fstream>
#include <string>
#include <stdlib.h>
#include <iterator>
#include <algorithm>

using namespace std;
void UpdateID();
void UpdateName();
void UpdateFamily();
void UpdateFatherName();
void UpdateStudentInfo();
void UpdateBirthDate();

int main()
{

rep:
    cout<<"Enter Student ID:";
    string sid;
    cin>>sid;
    ifstream f("students.txt");
    string s(sid);

    istreambuf_iterator<char> eof;
    if(eof == search(istreambuf_iterator<char>(f), eof, s.begin(), s.end()) )
    {
        cout << "Student ID \"" << s << "\" was NOT found!" << endl;
        getch();
        goto rep;
    }
    else
    {
        cout << "Student ID \"" << s << "\" found !" << endl;
        getch();
    }
    system("cls");
    cout<<"Enter Choice 1-5 :";
    cout<<"\n1.Update Student ID.";
    cout<<"\n2.Update Student Name.";
    cout<<"\n3.Update Student Family name.";
    cout<<"\n4.Update Student Father name .";
    cout<<"\n5.Update Student Birthday year.   info:\n\n";
    string line;
    ifstream myfile;
    myfile.open("students.txt");
    while(getline(myfile,line))
        {
        if(line=="ID:"+sid)
            {
                do
                {
                    cout<<"\t\t\t\t"<<line<<"\n";
                    getline(myfile,line);
                }while(line!="****");
            }
        }
    myfile.close();
    int i;
    cin>>i;

switch(i)
    {
    case 1:
            UpdateID();
            break;
        case 2:
            UpdateName();
            break;
        case 3:
            UpdateFamily();
            break;
        case 4:
            UpdateFatherName();
            break;
        case 5:
            UpdateBirthDate();
            break;
        default:
            cout<<"Error";
    }

}
void UpdateID()
{
    string NID,ID,line;
    cout<<"\nEnter ID :";
    cin>>ID;

    cout<<"\n";

    cout<<"Enter New ID :";
    cin>>NID;

    ifstream fp("Students.txt");

    while(getline(fp,line))
    {
        ofstream f("UpdatedStudents.txt",ios::app);

        if(line == "ID:" + ID)
            f<<"ID:" + NID<<endl;

        else f<<line<<endl;
    }
    fp.close();

    ofstream f;
    f.open("UpdatedStudents.txt",ios::app);
    ifstream fp1;
    fp.open("Students.txt");

    f.close();
    fp.close();

    remove("Students.txt");
    rename("UpdatedStudents.txt","Students.txt");
}

void UpdateName()
{
    string NName,Name,line;
    cout<<"\nEnter Name :";
    cin>>Name;

    cout<<"\n";

    cout<<"Enter New Name :";
    cin>>NName;

    ifstream fp("Students.txt");

    while(getline(fp,line))
    {
        ofstream f("UpdatedStudents.txt",ios::app);

        if(line == "Name:" + Name)
            f<<"Name:" + NName<<endl;
        else f<<line<<endl;
    }

    ofstream f("UpdatedStudents.txt",ios::app);

    f.close();
    fp.close();

    remove("Students.txt");
    rename("UpdatedStudents.txt","Students.txt");
}

void UpdateFamily()
{
    string NF,F,line;
    cout<<"\nEnter Family :";
    cin>>F;

    cout<<"\n";

    cout<<"Enter New Family :";
    cin>>NF;

    ifstream fp("Students.txt");
    while(getline(fp,line))
    {
        ofstream f("UpdatedStudents.txt",ios::app);
        if(line == "Family name:" + F)
            f<<"Family:" + NF<<endl;
        else f<<line<<endl;
    }
    ofstream f("UpdatedStudents.txt",ios::app);

    f.close();
    fp.close();

    remove("Students.txt");
    rename("UpdatedStudents.txt","Students.txt");
}

void UpdateFatherName()
{
    string NFN,FN,line;
    cout<<"\nEnter Father Name :";
    cin>>FN;

    cout<<"\n";

    cout<<"Enter New FatherName :";
    cin>>NFN;

    ifstream fp("Students.txt");

    while(getline(fp,line))
    {
        ofstream f("UpdatedStudents.txt",ios::app);
        if(line == "FatherName:" + FN)
            f<<"FatherName:" + NFN<<endl;
        else f<<line<<endl;
    }
    ofstream f("UpdatedStudents.txt",ios::app);

    f.close();
    fp.close();

    remove("Students.txt");
    rename("UpdatedStudents.txt","Students.txt");
}

void UpdateBirthDate()
{
    string NBD,BD,line;
    cout<<"\nEnter BirthDate :";
    cin>>BD;

    cout<<"\n";

    cout<<"Enter New BirthDate :";
    cin>>NBD;

    ifstream fp("Students.txt");

    while(getline(fp,line))
    {
        ofstream f("UpdatedStudents.txt",ios::app);

        if(line == "BirthDay year:" + BD)
            f<<"Birthday year:" + NBD<<endl;
        else f<<line<<endl;
    }
    ofstream f("UpdatedStudents.txt",ios::app);

    f.close();
    fp.close();

    remove("Students.txt");
    rename("UpdatedStudents.txt","Students.txt");
}

this piece of code works fine but it doesn't Rename The File!!! i'm so confused about it... any Suggestion?!
THanks!

[Chervil]

The code looks a bit muddled in places.
Take this function for example:

void UpdateID()
{
    string NID,ID,line;
    cout<<"\nEnter ID :";
    cin>>ID;

    cout<<"\n";

    cout<<"Enter New ID :";
    cin>>NID;

    ifstream fp("Students.txt");

    while(getline(fp,line))
    {
        ofstream f("UpdatedStudents.txt",ios::app);

        if(line == "ID:" + ID)
            f<<"ID:" + NID<<endl;

        else f<<line<<endl;
    }
    fp.close();

    ofstream f;
    f.open("UpdatedStudents.txt",ios::app);
    ifstream fp1;
    fp.open("Students.txt");

    f.close();
    fp.close();

    remove("Students.txt");
    rename("UpdatedStudents.txt","Students.txt");
}

Line 103 should be outside the while loop.
Before the rename, close each file.

Lines 112 to 118 serve no purpose.

You can also check that the rename was successful, and output an error message if it should fail.
New version. I changed fp and f to infile and outfile for clarity.

void UpdateID()
{
    string NID,ID,line;

    cout<<"\nEnter ID :";
    cin>>ID;

    cout<<"\nEnter New ID :";
    cin>>NID;

    ifstream infile("Students.txt");
    ofstream outfile("UpdatedStudents.txt",ios::app);

    while (getline(infile,line))
    {
        if (line == "ID:" + ID)
            outfile<<"ID:" + NID<<endl;
        else
            outfile<<line<<endl;
    }

    outfile.close();
    infile.close();

    remove("Students.txt");

    if (rename("UpdatedStudents.txt","Students.txt"))
        perror("rename");
}

[captain fantastic]

It gives me Error: "Rename:File exist" What should i do now?!

[Chervil]

I didn't get that particular error. But it would suggest the remove() function failed. You could check that too, in a similar way:
http://www.cplusplus.com/reference/cstdio/remove/