NOTE: in mathematics, the square root of a negative number is not real; in Java therefore, passing such a value to the square root function returns a value known as NaN (not-a-number). Given a double variable named areaOfSquare write the necessary code to read in a value, the area of some square, into areaOfSquare and print out the length of the side of that square. HOWEVER: if any value read in is not valid input, just print the message "INVALID". ASSUME the availability of a variable, stdin, that references a Scanner object associated with standard input.
import java.util.Scanner;

class square_root
{
public static void main (String[] args)
{
Scanner s=new Scanner(System.in);
System.out.print("Enter the area: ");

double areaOfSquare=s.nextDouble();
if(areaOfSquare<0)
{
System.out.println("INVALID");
System.exit(2);
}
System.out.println("The side of the square is: "
+Math.sqrt(areaOfSquare));
}
}