cs193p assignment solutions et al

cs193p – Lecture #8 View Controller Lifecycle, Autolayout

Please note, this blog entry is from a previous course. You might want to check out the current one.

View Controller Lifecycle

viewDidLoad is called after instantiation and outlet setting (geometry is not set yet!) – use for setup
viewWillAppear is called before the view appears on screen (geometry is available) – use for layout setup and updates which happened while the view was off screen
viewDidAppear
viewWillDisappear – use for cleaning up and saving states
viewDidDisappear

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cs193p – Lecture #7 Multiple MVCs

Please note, this blog entry is from a previous course. You might want to check out the current one.

The seventh lecture addresses the interaction of multiple model-view controllers – especially navigation controllers.

Segues

The links between two view controllers are called segues. They always create a new instance of the called MVC and need to initialize that MVC e.g. using prepareForSegue.

Segues can also be prevented from happening using shouldPerformSegueWithIdentifier.

Popover

Where tab-bar, split-view and navigation controllers are view controllers, popovers are not. Though preparing popover segues works similar, their destruction needs special care, making the calling view controller the delegate.

The lecture and its slides are available via iTunes named “7. Multiple MVCs”. The code for the psychologist demo is available on GitHub and at Stanford.

cs193p – Lecture #6 Protocols and Delegation, Gestures

Please note, this blog entry is from a previous course. You might want to check out the current one.

The sixth lecture contains theory interspersed with demos of the just learned topics.

Extensions

Extensions allow to add methods and properties to classes even if the source is not available. It is not possible to override existing methods and properties. New properties can not be used to store data.

Protocols

Protocols define APIs of methods and properties a caller should provide. It has no storage or implementation associated.

protocol SomeProtocol : class, InheritedProtocol1, InheritedProtocol2 {
    var someProperty: Int { get set }
    func aMethod(arg1: Double, anotherArgument: String) -> SomeType 
    mutating func changeIt()
    init(arg: Type)
}

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cs193p – Project #2 Assignment #2 Extra Task #3

Please note, this blog entry is from a previous course. You might want to check out the current one.

Add a new method, evaluateAndReportErrors(). It should work like evaluate() except that if there is a problem of any kind evaluating the stack (not just unset variables or missing operands, but also divide by zero, square root of a negative number, etc.), instead of returning nil, it will return a String with what the problem is (if there are multiple problems, you can simply return any one of them you wish). Report any such errors in the display of your calculator (instead of just making it blank or showing some weird value). You must still implement evaluate() as specified in the Required Tasks above, but, if you want, you can have evaluate() return nil if there are any errors (not just in the “unset variable” or “not enough operands” case). The push and perform methods should still return Double? (which is kind of a wasted evaluation, but we want to be able to evaluate your Extra Credit separate from the Required Tasks).

The definitions of the unary and binary operations get new parameters to pass optional error-test methods (and all their occurrences need to be adjusted for the new parameter):
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cs193p – Project #2 Assignment #2 Extra Task #2

Please note, this blog entry is from a previous course. You might want to check out the current one.

Add Undo to your Calculator. In Assignment 1’s Extra Credit, you might have added “backspace”. Here we’re talking about combining both backspace and actual undo into a single button. If the user is in the middle of entering a number, this Undo button should be backspace. When the user is not in the middle of entering a number, it should undo the last thing that was done in the CalculatorBrain.

Just for cosmetics change the name of the backspace button to “CE”:

cs193p - Project #2 Assignment #2 Extra Task #2 - Undo Button — cs193p – Project #2 Assignment #2 Extra Task #2 – Undo Button

cs193p – Project #2 Assignment #2 Extra Task #1

Please note, this blog entry is from a previous course. You might want to check out the current one.

Make your description have as few parentheses as possible for binary operations.

Add a new computed variable to the Op enum, which returns by the default the maximum integer value and for binary operations the value you set when defining the operation:

    private enum Op: Printable
    {
        ...
        case BinaryOperation(String, Int, (Double, Double) -> Double)
        ...
        var precedence: Int {
            get {
                switch self {
                case .BinaryOperation(_, let precedence, _):
                    return precedence
                default:
                    return Int.max
                }
            }
        }
    }

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cs193p – Project #2 Assignment #2 Task #12

Please note, this blog entry is from a previous course. You might want to check out the current one.

Your UI should look good on any size iPhone in both portrait and landscape (don’t worry about iPad until next week). This means setting up Autolayout properly, nothing more. 

… didn’t change anything there either. The two new memory buttons had already be there, just without functionality.