CS193P Calculator Assignment 2

Discussion in 'iOS Programming' started by kannn, Jul 11, 2011.

  1. kannn macrumors newbie

    Jul 11, 2011

    I'm having difficulty with CS193P assignment 2 (foundation calculator), and I can't seem to find any info on it online. This is from the latest, fall 2010 course entitled "developing apps for iOS." If you've completed assignment 2 or are in the process of doing it, please post! I'll be trying to work through it in the next couple of days.

    Also, are there other good places for discussing this course?
  2. RonC, Jul 11, 2011
    Last edited: Jul 11, 2011

    RonC macrumors regular

    Oct 18, 2007
    Ok, I'll bite (since I always plug this course): what difficulty are you having? I won't solve your problem for you, nor will I share my solution, but I can coach you through your problem.
  3. jnoxx macrumors 65816


    Dec 29, 2010
    Aartselaar // Antwerp // Belgium
    Like Ron said above me, what did you try, did you even start. etc.
    Because saying that you have a calc assignment, but that's about it, won't help us far by helping you.
  4. jiminaus macrumors 65816


    Dec 16, 2010
    If anyone interested, this course free online from Standard at http://www.stanford.edu/class/cs193p

    I think I've just found the thing that will get me to bridge my Cocoa knowledge to Cocoa Touch. :)
  5. kannn thread starter macrumors newbie

    Jul 11, 2011
    I just started learning programming, so when I started this assignment, it seemed overwhelming. Mostly, I was looking for a place where it had been discussed already, to help me wrap my head around it.

    I've worked through some of it now, but it's still confusing. Here is a specific:

    Xcode keeps yelling at me about using instance variables in class methods. I'm trying to enumerate through an expression to create an NSSet.
    I've overridden the expression getter to return a NSArray which keeps track of pressed buttons. It still builds fine, but what am I doing wrong here?

    Thanks for your help!
  6. kannn, Jul 12, 2011
    Last edited by a moderator: Jul 12, 2011

    kannn thread starter macrumors newbie

    Jul 11, 2011
    hmm.. I did something wrong in getting the internalExpression NSArray using it to set expression as it comes back as null. Again, I just started learning this. This is what I have:

    return internalExpression;
  7. jiminaus, Jul 12, 2011
    Last edited: Jul 12, 2011

    jiminaus macrumors 65816


    Dec 16, 2010
    Where do you initialize internalExpression?

    BTW The prerequisites stated in lecture 1 include previous object-oriented programming. Do you satisfy that prerequisite?
  8. balamw, Jul 12, 2011
    Last edited: Jul 12, 2011

    balamw Moderator


    Staff Member

    Aug 16, 2005
    New England
    Also available via iTunes U. Link: http://itunes.apple.com/us/itunes-u/developing-apps-for-ios-hd/id395605774

    EDIT: kannn I'd like to suggest that you take a look at the following two links:

    http://whathaveyoutried.com and http://www.mikeash.com/getting_answers.html

    When asking a question on a forum like this it helps to be as complete as you possibly can. This generally means providing some context for the code snippets you may post. Preferably, if those code snippets are compilable it really helps others see what you are up to and help you better.


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