1  import java.util.Scanner;

  2  

  3  /**

  4     This program shows how you can prompt for input that fulfills

  5     a certain condition. Try entering negative values, such as

  6     -2 or -0.5, to see how they are rejected.

  7  */

  8  public class DoLoop 

  9  {

 10     public static void main(String[] args)

 11     {

 12        Scanner in = new Scanner(System.in);

 13        

 14        double value;

 15        do

 16        {

 17           System.out.print("Enter a number >= 0: ");

 18           value = in.nextDouble();

 19        }

 20        while (value < 0);

 21        double root = Math.sqrt(value);

 22        System.out.println("The square root of the number is " + root);

 23     }

 24  }