swift学习03－快速学习常量变量

1.语法须知

2.常量

3.变量

1.开始学习Swift ，惯例：

输出“hello world！”字符串

     println("Hello World")

语法须知

2.常量变量

       //常量        let a = 1        let str:String = "hello"        let i :Int = 6                //变量        var b = 2        var str1 :String = "hello"        var j :Int = 9

补充：创建按钮和图片

         //创建按钮        var btn = UIButton()        btn.backgroundColor = UIColor.redColor()        btn.frame = CGRectMake(100, 100, 100, 100)        self.view.addSubview(btn)                        //创建UIImageView                var imageV = UIImageView()        imageV.frame = CGRectMake(100, 250, 50, 50)        imageV.image = UIImage(named: "002")        self.view.addSubview(imageV)