安卓开发

val name = "world"//常量，不可变
var greeting = "Hello"//变量，可变
var x: Int = 5
val c:  Int//初始化但是没有赋值

fun greet(name: String):String{
	return "Hello,$name"
}
fun sum(a: Int,b: Int) = a+b

val items = listOf("apple","banana","kiwifruit")
for(item in items){
	println(item)
}
for(index in items.indices){
    println("item at $index is ${items[index]}")
}

val items = listOf("apple","banana","kiwifruit")
var index = 0
while(index < item.size){
    println("item at $index is${items[index]}")
}

fun describe

class Person(val name:String){
	fun greet(){
		println("Hello,$name")
	}
}
open class shape
class Rectangle(val: height: Double, val Length: Double): Shape{
    val perimeter = (height + length)*2
}

@Composable
fun Greeting(name: String){
	Text(text="Hello,$name")
}