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
*/

// Modification of WindChill2.java to use if-else and nesting

public class WindChill3 {
   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) || (tempFahr > 50.)) {
         if (windSpeed < 4.0) {
            System.out.println("ERROR: windspeed must be >= 4 mph");
         }

         if (tempFahr > 50.0) {
           System.out.println("ERROR: temperature must be <= 50 F");
         }
      }
      else {
        // 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);
      }
   }
}