optionals1.swift

var score:Int?
score = 100
//if score is nil the if block will not work
/*if score has value, the if block create a new constant score and assign the score value to the new constant score which is unwrapped and available within the if block
*/
if let score = score{
    score
}
score ?? 0 //provide a default value when there is nil
score!  //when u sure the optional must have a value other than nil