5 replies to this topic

[eman ahmed]

what's the meaning of
- abstract data type
- heap and stack in general programming
- java has no preprocessor

[Momerath]

Abstract Data Type
Heap and Stack
Preprocessor

[eman ahmed]

I write this question to discuss the answer of it with another people and read a lot of ways to explain it.because I'm new in computer science and it's difficult for me to understant it
but at any way, thanks alot Momerath

[Alexander]

The linked articles are from an online encyclopedia (i.e. not a manual) so they should be more verbose in depth and provide ample examples from different people.

[WingedPanther]

If you want to discuss it, what parts of each do you find interesting/confusing?

[zeroradius]

1) Well an abstract class is something that can never be instanced. It is a class that can only be extended. So lets say I have a class called fighter, fighter would have methods in it that can be used by all fighters, so things like Attack(), Defend(), DoCantTouchThisDance(). But in this imaginary program lets say each fighter has to be more specific than just fighter. So I would have classes like Sameri(), Ninja(), gunner(). These last three classes would extend fighter but you would never want some one to make an instance of fighter because fighter has no body or special abilities so you would mark fighter abstract so that no one can make an instance of fighter. Abstract is basically your way of creating a default class with all the core components but not enough components to use on its own. (sorry if that made no sense, I suck at explaining things and I only learned about abstract data type a few weeks ago.) An abstract method on the other hand is a placeholder and is required to be over ridden. So in short abstract data has no real value until it is extended or overridden.

2) The stack is were methods being called and local variables live. It is were short lived things set. The heap is were Objects and INSTANCE variables set.

I think I got that all right (^_^) I don't know about the other as I am still working on learning Java myself.