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iOS Object-Oriented Swift 2.0 Classes Helper Methods

Danny Kilkenny
Danny Kilkenny
4,507 Points
Posted by Danny Kilkenny
Danny Kilkenny
4,507 Points

Why self.strength instead of just strength

I don't understand why Pasan uses "self.strength" instead of just using "strength". Could someone explain that to me. Here's the code below

Danny Kilkenny
Danny Kilkenny
4,507 Points
Danny Kilkenny
Danny Kilkenny
4,507 Points 
class Tower {
    let position: Point
    var range: Int = 1
    var strength: Int = 1

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

    }

    func fireAtEnemy(enemy: Enemy) {
        if inRange(position: self.position, range: self.range, target: enemy.position) {
            while enemy.life > 0 {
                enemy.decreaseHealth(factor: self.strength)

            }
        }
    }

    func inRange(position: Point, range: Int, target: Point) -> Bool {
        let availablePositions = position.surroundingPoints(withRange: range)
        for point in availablePositions {
            if (point.x == target.x) && (point.y == target.y) {
                return true
            }
        }
        return false
    }
}

1 Answer

Gabriel Mititelu
Gabriel Mititelu
5,881 Points

Hello, Danny.

Whenever you need to access/use an object's property within that object's definition, you must use the keyword self and dot notation.

To put this into perspective, when you want to access the strength property outside the Tower object, what do you do ?

You write:

Tower.strength

Similarly, when you need to access/use the strength property within the object, you write :

self.strength

Hope this helps. However, if it doesn't, do ask away.

Danny Kilkenny
Danny Kilkenny
4,507 Points
Danny Kilkenny
Danny Kilkenny
4,507 Points

Nah that makes perfect sense! Thanks!