Recently I had a phone interview where I got asked a variety of Java questions. This kind of thing is standard, and most of the questions were somewhat standard:

Working on Project Euler, there is a problem involving dice probabilities. The forum shows a variety of different solutions, some of them involving entirely too much typing (several people literally iterated through every possible combination of dice faces), and some of them were somewhat more considered.

Reading the comments, it reminded me of something my Russian mathematical modeling professor used to say back in school:

time + computation + thinking = constant

One of the final steps in developing your app before submission is adding an icon. This is a straightforward process:

• Create a 57x57 pixel PNG, name it "Icon.png". In must be exactly 57x57 pixels and it must also be a PNG.
  
• Add the file to your project's resources.
  
• Go into the Info.plist file and fill in the Value for "Icon file" to Icon.png, making sure that it matches the spelling and capitalization exactly.

Build and launch your app normally, the icon should be added and visible on your application.

Sometimes it is useful to see what malloc operations have been performed by a given application. Doing this is a fairly straightforward process that can be facilitated with the command malloc_history, but requires a little bit of setup for iPhone-specific apps since the console cannot be used directly.

...sign up to get paid tons of money to make statistical fallacies?

There is a fallacy I like to refer to as the "clifford fallacy" that the news media seems particularly prone to making: "If this dog keeps growing at its present rate, in five years it will be the size of Clifford!"

In the Java programming language there are both raw and wrapper objects to represent numbers. For example, int and Integer, double and Double, etc. If one wanted to add a numeric object to a Collection object, it required using the wrapper object rather than the raw type.

With the introduction of autoboxing in Java 1.5, moving between these types would largely be handled by the compiler, but there is still a distinction.

Just as with null types, Objective-C also requires that you wrap raw types before inserting them into objects or using them in variable argument lists where the type id is expected. To help us with this, cocoa provides NSNumber.

One of the really powerful libraries available to C++ programmers is the Standard Template Library (STL). While Cocoa has fantastic built-in classes, sometimes it is beneficial--especially when working with algorithms where raw numbers are being used and speed is more important--to use the STL.

Using the STL in Objective-C requires that you switch the file to use Objective-C++ by changing the file ending to .mm. After that you can import the various STL libraries normally: #import <vector>.

See Also:

• Standard Template Library Programmer's Guide
  
• The Objective-C 2.0 Programming Language: Using C++ With Objective-C

One thing that developers who are new to Objective-C will notice immediately are the number of null keywords. We have a choice of:

• nil
  
• Nil
  
• NULL

Under the hood there isn't much difference between these (as of this writing they are all defined exactly the same way), but by convention they have some subtle variations, and they have some odd behavior around them that it pays to understand.