Question

I’m learning java and have a bit of code I am trying to write that should round 24.9999999 to 25. Instead, it goes to 8.

import java.io.*;
import java.util.*;
public class RadiusOfCircle
{
    public static void main(String args[])
    {
        Scanner kbInput = new Scanner(System.in);
        System.out.print("What is the area? _");
        double area = kbInput.nextInt();
        System.out.println("Radius of your circle is " + Math.sqrt( area / Math.PI));

        double radius = Math.sqrt( area / Math.PI);
        System.out.println("\nChecking your work now...\n   area = pi*(r^2)\n   " + area + " = 3.14 * (" + radius + ")^2");
        double radiusSqrd = Math.pow(radius, 2);
        System.out.println("   " + area + " = 3.14 * " + radiusSqrd);
        System.out.println("   " + area + " = " + Math.PI * radiusSqrd);
        System.out.println(area + " = " + (Math.round(radiusSqrd)));
        System.out.println("Are the two values the same? \nIf yes, your code is correct! \nIf no, try again!");
    }
}

Also, when it asks for keyboard input of what the area is, I put in 25.

This is the output:

What is the area? _25
Radius of your circle is 2.8209479177387813

Checking your work now...
   area = pi*(r^2)
   25.0 = 3.14 * (2.8209479177387813)^2
   25.0 = 3.14 * 7.957747154594766
   25.0 = 24.999999999999996
25.0 = 8
Are the two values the same? 
If yes, your code is correct! 
If no, try again!

Answer 1

System.out.println("   " + area + " = " + Math.PI * radiusSqrd);
System.out.println(area + " = " + (Math.round(radiusSqrd)));

Shouldn’t that be:

double value = Math.PI * radiusSqrd;
System.out.println("   " + area + " = " +value );
System.out.println(area + " = " + (Math.round(value )));