Question

Request that the user enter the radius of a circle from the keyboard and store the value entered in the double variable, radius.

Answer 1

import java.util.Scanner;

public class Test {
public static void main(String args[]) {
Scanner s = new Scanner(System.in);
System.out.println("Enter the radius of a circle: ");
double radius;
do {
double temp = s.nextDouble();
radius = (temp < 0) ? -1 : temp;
if (radius == -1)
System.out.println("Enter the positive value");
} while (radius == -1);
}

}