Swift 3 Bottom Up: Ep3 - Control Flow and Optionals https://www.youtube.com/watch?v=Fwdu_RRqejk

control_flow_and_optionals.swift

// MARK: Control Flow

// MARK: if / else if / else

var numberTest = 3

if numberTest < 1 {
    print ("true")
} else if numberTest == 2 {
   print ("equals two")
} else {
    print ("Number is greater than 1 and does not equal two")
}


// MARK: while / repeat-while

var count = 0

while count != 10 {
    print(count)
    count += 1
}

count = 11

repeat {
    print (count)
} while count != 11


// MARK: for loops

for i in 0...10 {
    print(i)
}

var array = ["1":"cat", "2":"dog", "3":"bear"]

for (key, animal) in array {
    print (key)
}

// MARK: switch

switch "cat" {
    case "bear", "cat":
        print ("bear")
    case "dog":
    break
    default:
        print("default hit")
    break
}


// MARK: Optionals

var testValue: Int?

testValue = 1

if testValue != nil {
    print(testValue!)
}


// MARK: Optional Control Flow


if let unwrappedValue = testValue {
    print(unwrappedValue)
} else {
    
}

// guard let unwrappedIntValue = testValue else { return -1 }