struct Rectangle { var length: Double init(frombreadth breadth: Double) { length = breadth * 10 } init(frombre bre: Double) { length = bre * 30 } //不提供外部名字 init(_ area: Double) { length = area } } // 调用不提供外部名字 let rectarea = Rectangle(180.0) print("面积为: \(rectarea.length)") // 调用不提供外部名字 let rearea = Rectangle(370.0) print("面积为: \(rearea.length)") // 调用不提供外部名字 let recarea = Rectangle(110.0) print("面积为: \(recarea.length)")