笔记01 swift 基础语法

swift 常见数据类型 包括 值类型和引用类型

值类型 包括 枚举 optional 结构体（Bool Int Float Character String Array Dictionary Set 等）

引用类型 类 class

// 声明常量用 let 修饰创建的时候就确定不能改变，声明变量用 var 修饰

        let age1 = 10
        let age2 : Int = 20
        let age3 : Float = 30
        let age4 = { () -> Int in
            return 40
        }()
        
        let age5 = {
             50
        }()
        
        func getAge() -> Int {
            return 60
        }
        
        let age6 = getAge()

        
        print(age1,age2,age3,age4,age5,age6)
        //10 20 30.0 40 50 60
        
        var varage1 = 10
        var varage2 : Int = 20
        var varage3 : Float = 30
        var varage4 = { () -> Int in
            return 40
        }()
        
        var varage5 = {
             50
        }()
        
        var varage6 = getAge()

        
        print(varage1,varage2,varage3,varage4,varage5,varage6)
        //10 20 30.0 40 50 60

元组 是swift 相对OC的 可以灵活的声明多种数据组合。

        let err = (404,"Not Found")
        let err2 = (500,"No Data")
        var err3 : (Int,String,Int?)? = nil
        err3 = (100,"err",0)
        err3 = (101,"err",nil)
        var err4 : (errCode : Int, errMsg : String,otherCode : Int?)? = nil
        
        err4 = (102,"fdsfs",123)
        
        
        print(err)
        print(err2)
        print(err3!)
        print(err4!)
        
        let (code,msg,other) = err4!
        print("\(code),\(msg),\(other ?? 0)")

//(404, "Not Found")
//(500, "No Data")
//(101, "err", nil)
//(errCode: 102, errMsg: "fdsfs", otherCode: Optional(123))
//102,fdsfs,123