浏览器中输入网址：play.kotlinlang.org 进去后黏贴代码点击Run就可以看到结果了。

1. when 语句允许传入任何类型的参数，然后在when结构体中定义一系列条件
2. when还可以进行类型匹配

   /*** You can edit, run, and share this code.* play.kotlinlang.org*/
   fun main() {println("Hello, world!!!")val tom_score=getScore("Tom")println(tom_score)val tom_score2=getScore("Tom")println(tom_score2)val lily_score2=getScore("Lily")println(lily_score2)//演示when的类型匹配机制val intnum=0val doublenum=10.665678val longnum=10LcheckNumber(intnum)checkNumber(doublenum)checkNumber(longnum)}fun getScore(name:String)=if(name=="Tom"){86}
   else if(name=="Jim"){77}
   else if(name=="Jack"){95}
   else if(name=="Lily"){100}
   else {0}
   //下面考虑用when语句来改写上面的函数： when 语句允许传入任何类型的参数，然后在when结构体中定义一系列条件
   fun getScore2(name:String)=when(name){"Tom"->86"Jim"->77"Jack"->95"Lily"->100else ->0
   }
   //when还可以进行类型匹配
   fun checkNumber(num:Number){when(num){is Int ->println("Number is Int")is Double->println("Number is Double")else->println("Number not support")}
   }

   运行结果：

   Hello, world!!!
   86
   86
   100
   Number is Int
   Number is Double
   Number not support