OverridingvsExtending

// https://stackoverflow.com/questions/55446713/true-false-question-about-swift-subclass-superclass
class Person {

    var age : Int?
    
    func incrementAge() {
        guard age != nil else {
            age = 1
            return
        }
        age! += 1
    }
    
    func eat() {
        print("eat popcorn")
    }
}

var p1 = Person()
p1.incrementAge() // works fine

class Boy : Person{
    
    override func incrementAge() {
        age! += 2
    }
}

var b1 = Boy()
b1.incrementAge() // crashes, becasuse you literally overrode the behavior!!!


class GoodBoy : Person{
    
    override func incrementAge() {
        super.incrementAge()
        age! += 2
    }
}

var b2 = GoodBoy()
b2.incrementAge() // works fine.


class AlternateGoodBoy : Person{
    
    override func incrementAge() {
        guard age != nil else {
            age = 1
            return
        }
        age! += 2
    }
}

var b3 = AlternateGoodBoy()
b3.incrementAge() // works fine.

class Girl : Person{
    override func eat() {
        print("eat hotdog")
    }
}

var g1 = Girl()
g1.eat() // doesn't crash, even though you overrode the behavior. It doesn't crash because the call to super ISN'T critical

class Dad : Person {
    var moneyInBank = 0
    override func incrementAge() {
        super.incrementAge()
        addMoneyToRetirementFunds()
    }
    
    func addMoneyToRetirementFunds() {
        moneyInBank += 2000
    }
}

var d1 = Dad()
d1.incrementAge()
print(d1.moneyInBank) // 2000