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iOS Build a Simple iPhone App with Swift 2.0 Getting Started with iOS Development Swift Recap Part 2

Posted by Jared Welch
Jared Welch
5,616 Points

Code Challenge

I've been stuck of this and I need help!

In the editor you've been provided with two classes - Point to represent a coordinate point and Machine. The machine has a move method that doesn't do anything because most machines are motionless.

Your task is to subclass Machine and create a new class named Robot. In the Robot class, override the move method and provide the following implementation. If you enter the string "Up" the y coordinate of the Robot's location increases by 1. "Down" decreases it by 1. If you enter "Left", the x coordinate of the location property decreases by 1 while "Right" increases it by 1.

Note: If you use a switch statement you can use the break statement in the default clause to exit the current iteration.

classes.swift 
class Point {
    var x: Int
    var y: Int

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


class Machine {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

    func move(direction: String) {
        print("Do nothing! Im a machine!")
    }
}

// Enter your code below
ANDREA HEMPHILL
ANDREA HEMPHILL
14,484 Points

class Point { var x: Int var y: Int

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

}

class Machine { var location: Point

init() {
    self.location = Point(x: 0, y: 0)
}

func move(direction: String) {
    print("Do nothing! Im a machine!")
}

}

class Robot: Machine {

override func move(direction: String)  {

    switch direction {

    case "Up" : location.y += 1
    case "Down" : location.y -= 1
    case "Left" : location.x -= 1
    case "Right" : location.x += 1
    break
    default: "nothing"
    }

    print(location.y)            //this line is to check change

}

}

let sample = Robot() // x and y already initialized in Machine class, no need override in Robot class

sample.move("Down") // while writing in playground the code is sample.move(direction: "Down")

2 Answers

Moritz Lang
Moritz Lang
25,909 Points
Moritz Lang
Moritz Lang
25,909 Points

Hey Jared, can you please tell us on which part of the challenge you stuck? I could provide you with the solution righth now, but I think that it wouldn't help you in learning how to code by yourself.

Jared Welch
Jared Welch
5,616 Points

Overriding the subclass with the move method

ANDREA HEMPHILL
ANDREA HEMPHILL
14,484 Points
ANDREA HEMPHILL
ANDREA HEMPHILL
14,484 Points

``` class Point {

      var x: Int
      var y: Int

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

}

class Machine {

var location: Point
init() {
    self.location = Point(x: 0, y: 0)
}

func move(direction: String) {
    print("Do nothing! Im a machine!")
}

}

class Robot: Machine {

override func move(direction: String) {

    switch direction {

    case "Up" : location.y += 1
    case "Down" : location.y -= 1
    case "Left" : location.x -= 1
    case "Right" : location.x += 1
    break
    default: "nothing"
    }
print(location.y)   //this line is to check change

} }

let sample = Robot() // x and y already initialized in Machine class, no need override in Robot class sample.move("Down") // while writing in playground the code is sample.move(direction: "Down")