What are coroutines used for and what tasks do they help solve in programming?

Coroutines are lightweight threads or functions that can suspend their execution and resume later without blocking the main thread.

In programming, coroutines are used to simplify asynchronous code and manage concurrency, allowing you to write sequential code that executes asynchronously.

For example, in Android, coroutines help perform input-output operations (loading data from the network, working with a database) without blocking the UI thread, which improves app responsiveness.

Example in Kotlin:

import kotlinx.coroutines.*

fun main() = runBlocking {
    launch {
        delay(1000L)
        println("Coroutine finished")
    }
    println("Program continues")
}

Here, delay is a non-blocking pause that allows other coroutines to run during this time.