Thursday, May 16, 2013

Matchismo on iOS

This is the first assignment for the course CS193P at Stanford 2013 winter session. It shows how the "MVC" structure works, and also includes really good coding style in objective-oriented programming.

Some interesting stuffs I would like to share is as below:

  1. Connecting the "View" related events or properties by dragging the object from GUI programming interface to text code. Cool.
  2. NIL pointer design, I've written things about this in last post.
  3. General initialisation design. Objects in objective-C mostly have the some usage in initialisations, setters/getters, function callings, etc. It's easy for the developers to learn some basic examples and apply on different occasions.
  4. Auto-complete editing design in Xcode. Although this feature, auto-complete while typing the code, is not new stuff, it's still the best auto-complete mechanism I've ever seen. It's fast, and smart. It allows you to jump to next blank in a very short time. While writing the program, you spent very little time on typing. Around 80%~90% of the code can be done by the auto-complete function, only the new names for object/function/etc are needed to be typed completely. At last, Xcode also generates those an annoying special characters in the code, like "", [], {}, etc.
Finally, the developing environment for iOS is not only including great designs but also so much fun.

Saturday, May 11, 2013

NIL Pointer in Objective C

In many programming languages, we do the checking if the pointer is null (equally, 0) or not before we start to grab the content. However, in Objective C, there's no need to do this. The design makes you no need to do so.

When a pointer has no object points to, it's automatically storing the value 0, which we call a NIL pointer. And, we can complete our other designs without checking the pointer is NIL or not because that function calls just do nothing on NIL pointers, and return 0.

Take one example I learned in the class,
if ([card.contents isEqualToString:self.contents] ){ score = 1; }
No need to card.contents is NIL or not. If it's NIL, isEqualToString just simply skip it and return 0, which may cause the if-statement failed, which is also the right thing we want.