Thread: Deleting Record in Binary File without Temporary File

If you just want a flat binary file, and you don't want to use a secondary file, and you don't want to read the entire file into memory, and you want to use standard C++, and you apparently do want all this with the exception of clear screen, you need to set aside one identifier that says "this record has been deleted". Your actual file would still be 88 bytes, or whatever, but you will have records that are empty. Say you use negative one after deleting record four you'd have:

1 A
2 B
3 C
-1 Empty Record

[Edit]
Also, your approach to this is very wrong if you are doing what I think you are doing.

The data you are managing shouldn't be part of the manager class.
You shouldn't be changing `this` with respect to `this` identity when you remove a record from a file being managed.
I could go on, but I'd like to see you fix the code first.
[/Edit]

Originally Posted by Zeus_

My homework problem:

Write a menu driven program to implement Adding and Deletion of Records in a binary file. (Note: Deletion to be performed without a temporary file). Use the following class:

Code:

class Manager
{
       int   ID;
      char Name[20];

};

As a solution, should I be reading the details into another instance of Manager instead of "this" and accordingly be rewriting?
I didn't understand the part where you say "The data you are managing shouldn't be part of the manager class.
You shouldn't be changing `this` with respect to `this` identity when you remove a record from a file being managed.". Could you please explain more? At school, reading a binary file record by record is the only thing I've learnt till now. Please redirect me to sites where I can learn more ways to do so...

Thanks for your time @phantomotap!

Yes. You should probably be reading into a temporary instance of the class.

There is no reason for the manager class to have the data members it has, but if that's what you were given, I suppose that is what you should use.

The recommendation comes from object oriented design.

If you have a `Manager s(1, "A");`, the identity of the class, the data members `(1, "A")`, should not change to a possibly random identity, say `(4, "D")`, just because the user of class deleted an unrelated record. It makes no sense and is unexpected.