Category Archives: Objective C

Doing Math in Objective C

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One thing you will find you need to do in any programming language is do math. Here are some useful math functions for the Objective C language. I give a little bit of a comparison to Visual Basic for those who know that language. They are provided in no special order:

  • fabs() – Gets the absolute value of the value in parentheses. Works like ABS() function in Visual Basic. fabs(-123) = 123, fabs(34) = 34.
  • ceil() – Find the ceiling integer. Kind of like rounding up. Same as INT(x+1) in Visual Basic.  ceil(3.1) = 4.
  • floor() – Find the floor integer. Kind of like rounding down. Same as INT(x) in Visual Basic. floor(3.6) = 3.
  • exp() – Find the exponential value.
  • pow() – Raise a number to the power. pow(3,6) = 3^6 in Visual Basic.
  • rand() – Generate a pseudo random number. Function is RND(x) in Visual Basic. A good discussion on random numbers in Objective C can be found here.
  • srandom() – Generate a seed for the random number generator. This is done with the Randomize statement in Visual Basic.
  • sqrt() – Find out the square root of a number. sqrt(x) = x^(1/2) in Visual Basic.

How to Create Class Categories in Objective C

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Note: Video is Best Viewed in Full Screen Mode

As I began refining some sample code for making Universal Apps for the iPhone and iPad, I sought a way to make my code as concise as possible. I needed to determine if the app was running on an iPad or iPhone/iPod Touch and use it to my advantage. This basic information is contained in the UIDevice class.

Unfortunately, using:

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