Thanks for all that code but how would that be used in my program as I have two member types, a full member and a young member type. These member types have there own classes and a derived from a partent Member class.

It's exactly C++ battlefield!

Declare class Member as an abstract class (with pure virtual functions), define these virtual functions in FullMember and YoungMember classes, use vector<Member*> in your variant of my PlainDb - that's all. Polymorphism works!..

I suspect that it's a true aim of your (homework?) task.

I wonder how you guessed that! Thanks for the help guys.

It might not be that simple if you also need to keep track of whether a member is full or young. You would need to output that in some form to your text file, and then as you read the data, create an appropriate object based on whether its a full or young member.

Yes, it's (one of) a technical problem with deserializing. Fortunately, there are many ways to simplify its solution. We need an arbiter who make a decision (in the PlainDb::load() from my snippet equivalent): new FullMember() or new YoungMember ...

Are you saying that it would be better to output both member types in one text file?

you could add one more field to the structure which specifies the 'member_type' and write that to your file then when you load the file based on the 'member_type' you can create the correct object type.

Don't shoot me for this, but where do I write the structure for member type (I have two child classes and one parent class that defines the objects) and where do I put "vector<Member*>" and what do I do with it?

you dont need a separate structure for a member_type, use the exisiting structure which coolgamer had suggested and add another field to it.

i think best would be that you try to write some code from whatever you have understood till now and post it, then we can take it from there.

How do you load the data from the txt files into a vector, thats what I can't understand. I have changed my program so that it only uses on text file, but each line of that files starts with either Full Mem or Young Mem depending on the account stored. Also the Young member has 4 pieces of data stored with it wheras the full mem only has three.

I want the program to call up this data so that it can be used in the accounts assciated functions i.e. deposit money, withdraw or calculate the interest etc.