How to convert nanoseconds to seconds using the TimeUnit enum? Ask Question

Question

How to convert a value from nanoseconds to seconds?

Here's the code segment:

import java.io.*;

import java.util.concurrent.*; 

..

class Stamper { 

public static void main (String[] args) { 

long start = System.nanoTime(); 

//some try with nested loops 

long end = System.nanoTime(); 

long elapsedTime = end - start;

System.out.println("elapsed: " + elapsedTime + "nano seconds\n");

//convert to seconds 

TimeUnit seconds = new TimeUnit(); 

System.out.println("which is " + seconds.toSeconds(elapsedTime) + " seconds"); 

}}

The error is

Stamper.java:16:  enum types may not be instantiated.

What does this mean?

Answer 1

Well, you could just divide by 1,000,000,000:

long elapsedTime = end - start;

double seconds = (double)elapsedTime / 1_000_000_000.0;

If you use TimeUnit to convert, you'll get your result as a long, so you'll lose decimal precision but maintain whole number precision.