import junit.framework.TestCaseimport org.junit.Testimport scala.runtime.RichByte//数据类型class Demo2 extends TestCase {        //规则1 定义整数类型变量时,默认数据类型是java中int类型    //规则2 当数值范围超过int值区间,会编译失败,需要在数值后面加上L,讲类型转为long类型     //规则3 定义小数类型变量时,默认数据类型是java中double类型    //规则4 当定义小数数据类型变量时,可以在值后尾添加D,或者F,这样scala会自动转为 double,float类型    //以上规则都是建立在 scala ---隐式推断变量数据类型    //规则5 显示定义具体数据类型变量    //规则6 当一行代码中有多条语句时,才需要用分号隔开     def test_show_datatype(){                  //整数          var k1 = 1        var k2 = 10001        var k3 = 200001        var k4  = 20000000000l                //小数        var k5 = 1.1        var k6 = 1.1d        var k7 = 1.1f                //布尔值        var k8 = true                //字符型        var k9 = 'M'                var k10 = "YOYO"                val m1:String = ""        val m2:Any = 1    }        //scala 数据类型    def test_Rich(){       println("Scala 数据类型");        val m1:Byte = 1        //RichByte       val m2:Char = 10       //RichChar       var m8:Short = 11      //RichShort       val m3:Int  = 100      //RichInt       val m4:Long = 1000L    //RichLong       val m5:Float = 100     //RichFloat       val m6:Double = 100    //RichDouble       val m7:Boolean = false //RichBoolean        val b1 = m1.!=(10);       val M9:String = "CS" //StringOps       M9.indexOf(1);       SUM(M9)       var demo2 = new Demo2       demo2.SUM(M9)       demo2 SUM M9       demo2.goto(10, 20, 1)       demo2 goto (5,10,2)     }        def SUM(x: String){       println(x);       val u1 = x(0)       println(u1)    }        def goto(x:Int,y:Int,z:Int){      val r = x*y*z      println(r)    }    }