[코틀린 기초] 12. 반복문 (for, forEach)

코틀린을 활용한 여러가지 반복문을 알아보자

package com.example.myapplication.Kotlin

fun main(array: Array<String>){
    var a = mutableListOf<Int>(1,2,3,4,5,6,7,8,9)

    //반복 1
    for(item in a){
        if(item == 5){
            println("다섯번째")
        }else {
            println(item)
        }
    }

    //반복 2
    for((index, item) in a.withIndex()){
        println("index : $index , value : $item")
    }

    // 반복 3
    a.forEach{
        println(it)
    }

    println()
    //반복 4
    a.forEach{ item ->
        println(item)
    }

    //반복 5
    a.forEachIndexed { index, item ->
        println("index : $index , value : $item " )
    }

    //반복 6
    for( i in 0 until a.size){
        // until은 마지막 포함 x
        println(a[i])
    }

    println()
    //반복 7
    for( i in 0 until a.size step (2)){
        println(a[i])
    }

    println()
    //반복 8
    for(i in a.size - 1 downTo(0)){
        println(a[i])
    }

    println()
    //반복 9
    for(i in a.size - 1 downTo(0) step (2)){
        println(a[i])
    }

    println()
    //반복 10
    for(i in 0 .. a.size-1){
        // ..은 마지막포함
        println(a[i])
    }

    //반복 11
    var st:Int = 0
    var ed:Int = 5
    while(st < ed){
        println("Hello")
        st++
    }

    //반복 12
    var st1:Int = 0
    var ed1:Int = 5
    do {
        println("good")
        st1++
    }while(st1 < ed1)
}