measure and show elapsed time

elapsedTime.scala

// from https://biercoff.com/easily-measuring-code-execution-time-in-scala/

def time[R](block: => R): R = {
    val t0 = System.nanoTime()
    val result = block    // call-by-name
    val t1 = System.nanoTime()
    println("Elapsed time: " + (t1 - t0) + "ns")
    result
}

///// time{ 2+2}

import java.util.concurrent.TimeUnit
val start = System.nanoTime()

// something to do

val end = System.nanoTime()
val difference = end - start
println("Total execution time: " +  
      TimeUnit.NANOSECONDS.toHours(difference) + " hours " +
    ( TimeUnit.NANOSECONDS.toMinutes(difference) -  TimeUnit.HOURS.toMinutes(TimeUnit.NANOSECONDS.toHours(difference)))   + " min " +
    ( TimeUnit.NANOSECONDS.toSeconds(difference) -  TimeUnit.MINUTES.toSeconds(TimeUnit.NANOSECONDS.toMinutes(difference))) + " sec " +
      " - " + difference + " nSec (Total)")