Wednesday, July 11, 2007

Random Notes

Diffference between SDI and MDI :
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1.What is the difference between simple form & MDI form?

MDI (Multi Document Interface) Form is form that can hold multi forms inside it. Examples -

MDI - Excel
SDI - Notepad

MDI Form Contain the Multiple MDICHILD form and Dialog form
But Simple for do not able to contain any form in it.

MDI forms are certainly helpful for embedding other forms. Something that a lot of people don't know, is that you can make any window that has an hWnd, the child of another form with a simple API call. So, essentially, even top level windows CAN be MDI, but in practice, this is rude.

what is OpenDML ?

OpenDML is an extension to the original Video for Windows (VfW) file format.
It was drawn up to overcome the original 2GByte file length restrictions in avi files. (AVI files must be less than 2 GB size previously, this problem is overcome
by OpenDML)

Object modelling :
Object modelling is useful for designing computer systems, whether those systems are to be implemented in object-oriented languages or not.Most designs are likely to need more than an object-oriented language, such as a database. Object modelling also has a use outside of the design of computer systems. It is an excellent analysis method, and it can be used in business process reengineering, in social science research, or any complex environment where it is important to capture the structure and functionality of some world.

Design is a process which involves
communication
creativity
negotiation
agreement
It is a human process, to produce products for human consumption. Too often the communication, negotiation and agreement aspects are left
Object modelling provides a notation which is clear, consistent, and which can be used to communicate within a software development team, and with the clients and other third-parties which the team need to deal with.
Object modelling consists of looking for objects. Of course, there has to be some boundary. Even sitting at my desk I can see more objects than I could reasonably list. But that is where the beauty of object modelling comes in. It uses observation.
Objects can be described by their attributes and operations. Attributes are the changeable characteristics of an object. Cats have colour, size, weight and a preference for either Kit-E-Kat or Whiskers. Operations are the things an object does or can have done to it. Cats can catch mice, eat, miaow, worm up to owners, and be stroked. In our notation we draw an object such as a cat like this.

Object modelling is about finding objects, their attributes and their operations, and tying them together in an object model. Nothing more. Here are some more objects: Object modelling can be used to design lots of things.

what is Delegation :
The behaviour of an object which is made up of other objects is usually defined by the behaviour of the smaller objects. For example To start a car, you start the engine. Thus the start operation on the car involves calling the start operation on the engine. This is known as delegation. The engine then will switch on the ignition system, switch on the starter motor then switch off the starter motor. This is further delegation.

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