Compiler says "error: assignment of read-only location"

[SomeAmazingGuy]

I have made a program that uses 3 classes that each do a specific task. The base class is used to declare 2 pure virtual functions that are instantiated in the other 2 derived classes.

One derived class uses one virtual function to get an entire copy of a file and store it in a c-string array, and the other derived class uses the second virtual function to "transform" all letters in the file to upper case (and store it in a c-string array). But the compiler says that there is an error "assignment of read-only location".

I have been trying to correct this problem but i can't seem to actually correct it. Any help is appreciated.

P.S the program is not finished


Here is the driver program that tests all the classes

#include <iostream>
#include <fstream>
#include "Transform class.h"
#include "OriginalFile class.h"

using namespace std;

int main ()
{


    fstream file;
    string name;

    cout << "Please type in a name of a file" << endl;
    cin >> name;

    file.open (name.c_str() , ios::in | ios::out | ios::app);

}

This is a derived class that is derived from the "FileFilter class"

#define TRANSFORM CLASS_H
#include "FileFilter class.h"
#include <fstream>
using namespace std;

class Transform : public FileFilter
{
   char lines [1000];

public:

    virtual char transform (char, fstream &) const;



};

char Transform::transform (char ch, fstream &file) const
{
        int n = 0;
        int m = 0;
        int b = 0;
        char byte;


        while (!file.eof())
        {
            file.get (byte);
            lines[n] = byte;     //assignment of read only location?
            n++;
        }

        file.seekg (0, ios::beg);

        while (!file.eof())
        {
            lines[m] = toupper(lines[m]);
            m++;
        }

        file.seekg (0, ios::beg);


        while (!file.eof())
        {
            cout << lines[b];
            b++;
        }
}

This is another class that is derived from the "FileFilter" class

#include <fstream>
#define FILE FILTER_H
#define ORIGINALFILE CLASS_H
#include "FileFilter class.h"
using namespace std;

class OriginalFile : public FileFilter
{
protected:

    char lines_ [1000];


public:

    virtual void readFile (fstream &) const;


};


void OriginalFile::readFile (fstream & file1) const
{
        int n = 0;
        int m = 0;
        char byte;

        while (!file1.eof())
        {
            file1.get (byte);
            lines_[n] = byte;
            n++;
        }

        file1.seekg (0, ios::beg);

         while (!file1.eof())
        {
            cout << lines_[m] << endl;
            m++;
        }
}

And here is the base class

#define FILEFILTER CLASS_H
#include <fstream>

using namespace std;

class FileFilter
{
public:

    virtual char transform (char, fstream &) = 0;
    virtual void readFile (fstream &) = 0;

};

Also, the compiler says "error: redefinition of FileFilter class" But i dont see where i have redefined the filefiler class..

[kbw]

But the compiler says that there is an error "assignment of read-only location".

Exact error message please.

[Jaybob66]

looks like you need to guard your headers....

#ifndef FILEFILER_CLASS_H            <<<<<<<<<<< add this

#define FILEFILTER CLASS_H
#include <fstream>

using namespace std;

class FileFilter
{
public:

    virtual char transform (char, fstream &) = 0;
    virtual void readFile (fstream &) = 0;

};

#endif                  <<<<<<<< and this 

alternatively, if you are using MSVC you can pragma it instead.

#pragma once
#include <fstream>

using namespace std;

class FileFilter
{
public:

    virtual char transform (char, fstream &) = 0;
    virtual void readFile (fstream &) = 0;

};

oh, and as you will find, each derived class MUST implement all pure virtuals of the base class, you can't pick and choose.