JuniorTheoryCommon

What does the program print (lines separated by spaces)?

KOTLIN

import kotlinx.coroutines.*

fun main() = runBlocking {
    launch {
        delay(100)
        println("A")
    }
    println("B")
}

B A

Expecting A B: thinking launch runs its block to the end before moving on. It only starts the coroutine, and main prints B before the coroutine runs a single line.
Expecting only B: thinking the program ends with the last line of main. runBlocking does not finish until every coroutine it started is done.

JuniorTheoryCommon

KOTLIN

import kotlinx.coroutines.*

fun main() = runBlocking {
    launch {
        delay(100)
        println("A")
    }
    println("B")
}

B A

Expecting A B: thinking launch runs its block to the end before moving on. It only starts the coroutine, and main prints B before the coroutine runs a single line.
Expecting only B: thinking the program ends with the last line of main. runBlocking does not finish until every coroutine it started is done.