Question

import kotlinx.coroutines.*

// TODO 1
fun sum(valueA: Int, valueB: Int): Int {
    return 0
}

// TODO 2
fun multiple(valueA: Int, valueB: Int): Int {
    return 0
}

fun main() = runBlocking {

    println("Counting...")

    val resultSum = async { sum(10, 10) }
    val resultMultiple = async { multiple(20, 20) }

    // TODO 3
    println()
}

TODO 1:
Change it to suspend function with the following conditions:
Has a waiting time of 3 seconds before the next operation runs.
Returns the value of the sum of valueA and valueB.

TODO 2:
Change it to suspend function with the following conditions:
Has a waiting time of 2 seconds before the next operation runs.
Returns the value of the multiplication valueA and valueB.

TODO 3:
Add a function to print the deferred values of the resultSum and resultMultiple variables on the console.

If run, the console will display the text:
Counting ...
Result sum: 20
Multiple results: 400

Answer 1

Below is the solution:

import kotlinx.coroutines.*

// TODO 1
fun sum(valueA: Int, valueB: Int): Int {
    Thread.sleep(3_000) //wait 3 second
    val sum = valueA + valueB
    return sum
}

// TODO 2
fun multiple(valueA: Int, valueB: Int): Int {
    Thread.sleep(2_000) //wait 2 second
    val mul = valueA * valueB
    return mul
}

fun main() = runBlocking {

    println("Counting...")

    val resultSum = async { sum(10, 10) }
    val resultMultiple = async { multiple(20, 20) }

    // TODO 3
    print("Result sum: ${resultSum.await()}") //print the result of sum
    println()
    print("Multiple results: ${resultMultiple.await()}")   //print the result of multiply
}

sample output:

Counting...

Result sum: 20

Multiple results: 400