↓
↓
混乱するので
struct Klass { var a: Bool? = nil var b: Bool? = nil } let klass: Klass? = Klass(a: false, b: nil) let hoge = 3 if klass?.a == false { print("aはfalse") } if hoge == 3 && klass?.a == false { print("aはfalse") } if klass?.b == false { print("bはfalse") } if hoge == 3 && klass?.b == false { print("bはfalse") }
結果は。
aはfalse aはfalse
A hill is usually less than 984-1968 feet (300-600 meters) whereas a mountain is usually higher than 1968 feet (600 meters).