import java.util.Scanner; // For user input

/**
* Compute wind chill given temp. in Fahrenheit and wind speed in miles per hour
* Ref.: J. Adams et al., C++: An Intro. to Computing
*
* @author (Michael Branicky)  09/10/2007
*/

// Same as WindChill.java BUT adds two "if" statements

public class WindChill2 {
   public static void main(String args[]) {
      // Declaration of variables to be used
      double windSpeed, tempFahr, vPart, windChill;
  
      // Create Scanner to obtain input from command window
      Scanner input = new Scanner( System.in );

      // Get user input
      System.out.print("Enter temp. (F): ");
      tempFahr = input.nextDouble();
      System.out.print("Enter wind speed (mph): ");
      windSpeed = input.nextDouble();

      if (windSpeed < 4.0) {
         System.out.println("ANSWER NOT VALID: windspeed must be >= 4 mph");
      }

      if (tempFahr > 50.0) {
        System.out.println("ANSWER NOT VALID: temperature must be <= 50 F");
      }

      // compute v_part
      vPart = 0.474677 - 0.020425 * windSpeed + 0.303107 * Math.sqrt(windSpeed);

      // compute wind chill
      windChill = 91.4 - vPart * (91.4 - tempFahr);

      // Display output
      System.out.println("Wind Chill index = " + windChill);
   }
}