class calculations { let a: Int let b: Int let res: Int init(a: Int, b: Int) { self.a = a self.b = b res = a + b print("Self 内: \(res)") } func tot(c: Int) -> Int { return res - c } func result() { print("结果为: \(tot(c:20))") //swift 3.0 版本之前是 print("结果为: \(tot(20))") print("结果为: \(tot(c:50))") //swift 3.0 版本之前是 print("结果为: \(tot(50))") } } let pri = calculations(a: 600, b: 300) let sum = calculations(a: 1200, b: 300) pri.result() sum.result()