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iOS Object-Oriented Swift 2.0 Classes Instances of Classes

Posted by Matt Conway
Matt Conway
1,572 Points

Init method

I am not sure what to put inside the init method!

Challenge Task 1 of 1

Let's get in some practice creating a class. Declare a class named Shape with a variable property named numberOfSides of type Int.

Remember that with classes you are required to write an initializer method.

Once you have a class definition, create an instance and assign it to a constant named someShape.

/Users/mattconway/Desktop/Screen Shot 2016-01-23 at 5.03.08 PM.png

classes.swift 
// Enter your code below
class Shape {
var numberOfSides: Int
init(x: Int, y: Int) {

}

let someShape = Shape(x: Int, y: Int)
}
Dale Bailey
Dale Bailey
20,269 Points

You do not need x & y, please see my answer

4 Answers

Nathan Tallack
Nathan Tallack
22,159 Points
Nathan Tallack
Nathan Tallack
22,159 Points

Very close. You just need to set that numberOfSides property inside your method. We do that by referring to it with the self. prefix. We also need to give it some values. For your example I am using 4 as the number of sides.

You also need to pass in some values when you are declaring your someShape. For your example I am using 2 and 2. :)

Your code would look like this.

class Shape {
  var numberOfSides: Int

  init(x: Int, y: Int) {
    self.numberOfSides = 4
   }
}

let someShape = Shape(x: 2, y: 2)
Matt Conway
Matt Conway
1,572 Points

You were right, it was a typo mistake that I made, so now everything is ok. Thanks for your help

Dale Bailey
Dale Bailey
20,269 Points

You do not need x & y, please see my answer

Dale Bailey
Dale Bailey
20,269 Points
Dale Bailey
Dale Bailey
20,269 Points

Hi Nathan Tallack's answer is wrong, I don't know why people are trying to pass in x & y as it did not ask for them, it is not necessary. Define a class called "Shape", create an Int var called "numberOfSides", initialise it and then assign and instance of "Shape" to a constant called "someShape"

class Shape {
  var numberOfSides : Int
  init(numberOfSides: Int) {
    self.numberOfSides = numberOfSides
  }
}

let someShape = Shape(numberOfSides: 8)
Steven Ossorio
Steven Ossorio
1,706 Points

Hey Dale, Thanks for your explanation. It's true, nothing was asked in regards to x and y. Just a heads up, your variable has a little issue. I know you meant var numberOfSides: but just letting you.

jeremiahjacquet
jeremiahjacquet
16,885 Points
jeremiahjacquet
jeremiahjacquet
16,885 Points

Dale Bailey Your solution is the correct way as it does not specify x and y values. The only issue i am getting is you cannot assign the the property to itself 'self.numberOfSides = numberOfSides'

I added an int as the an initial value and got no errors in the playground.

class Shape {

var numberOfSides: Int

init(numberOfSide: Int) {
    self.numberOfSides = 8
}

}

let someShape = Shape(numberOfSide: 6)

Matt Conway
Matt Conway
1,572 Points
Matt Conway
Matt Conway
1,572 Points

I typed exact code you listed in Playgrounds, got 3 errors. Also typed in Challenge, got a whole bunch of errors!! Here is what it said:

class Shape Int { var numberOfSides: Int init(x: Int, y: Int) { self.numberOfSides = 4 } } let someShape = Shape(x: 2, y: 2)

swift_lint.swift:4:13: error: expected '{' in class class Shape Int { ^ swift_lint.swift:4:17: error: statement cannot begin with a closure expression class Shape Int { ^ swift_lint.swift:4:17: note: explicitly discard the result of the closure by assigning to '_' class Shape Int { ^ _ = swift_lint.swift:6:7: error: initializers may only be declared within a type init(x: Int, y: Int) { ^ swift_lint.swift:4:17: error: braced block of statements is an unused closure class Shape Int { ^ swift_lint.swift:4:17: error: expression resolves to an unused function class Shape Int { ^ swift_lint.swift:10:26: error: expected ',' separator let someShape = Shape(2: Int, 2: Int) ^ , swift_lint.swift:10:26: error: expected expression in list of expressions let someShape = Shape(2: Int, 2: Int) ^ swift_lint.swift:10:26: error: expected ',' separator let someShape = Shape(2: Int, 2: Int) ^ , swift_lint.swift:10:34: error: expected ',' separator let someShape = Shape(2: Int, 2: Int) ^ , swift_lint.swift:10:34: error: expected expression in list of expressions let someShape = Shape(2: Int, 2: Int) ^ swift_lint.swift:10:34: error: expected ',' separator let someShape = Shape(2: Int, 2: Int) ^ ,