import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

/* Java application that computes an NFL passer rating, given the relevant
** input, which is provided by the user in response to a sequence of prompts.  
** (If a command line argument is provided, input is read from the file that
** it names.)
**
** Authors: R. McCloskey and < STUDENT's NAME >
** Collaborated with: ...
** Known defects: ...
*/

public class PasserRatingNFL {

   private static Scanner input;  // For reading input
   private static boolean echo;   // true iff input should be printed

   public static void main(String[] args) {
      // Establish a Scanner that reads from the keyboard (unless there is a
      // command line argument, in which case it reads from the file it names).
      establishScanner(args);

      // Display a greeting.
      System.out.println("Welcome to the NFL Passer Rating application!\n");

      // For each input, prompt the user for it, read the response, and
      // store the response in the corresponding input variable.
      int attempts = getInt("Enter # of passes attempted:> ");
      int completions = getInt("Enter # of completed passes:> ");
      int yards = getInt("Enter # of passing yards:> ");
      int numTDs = getInt("Enter # of TD passes:> ");
      int intercepts = getInt("Enter # of passes intercepted:> ");

      double passRating = passerRating(attempts, completions,  
                                       yards, numTDs, intercepts);

      System.out.print("\nNFL Passer Rating: ");

      // MISSING CODE HERE

      System.out.println("Goodbye.");
   }


   /* Given the relevant raw passing statistics, via its formal parameters,
   ** computes and returns the NFL passer rating.
   */
   public static double passerRating(int attempts, int completions,
                                     int yards, int numTDs, 
                                     int interceptions) {
      return 0.0;   // STUB
   }

   /* Returns the component of the passer rating based upon completion
   ** percentage (i.e., the completion percentage factor). 
   */
   public static double completionPctFactor(int attempts, int completions) {
      return 0.0;   // STUB
   }

   /* Returns the component of the passer rating based upon
   ** yards per pass attempt (i.e., the yards per attempt factor). 
   */
   public static double yardsPerAttFactor(int attempts, int yards) {
      return 0.0;   // STUB
   }

   /* Returns the component of the passer rating based upon 
   ** touchdown frequency (i.e., the touchdown percentage factor). 
   */
   public static double touchdownPctFactor(int attempts, int numTDs) {
      return 0.0;  // STUB
   }


   // MISSING METHOD CAN BE PLACED HERE



   //---------------------------------------------------------------
   // DO NOT MODIFY WHAT FOLLOWS!!

   /* Prints the given prompt, reads the response (assumed to be an
   ** integer) via the 'input' Scanner, and returns it.  If appropriate,
   ** the response is printed.
   */
   private static int getInt(String prompt) {
      System.out.print(prompt);
      int response = input.nextInt();
      if (echo) { System.out.println(response); }
      return response;
   }

   /* Binds to global variable 'input' a Scanner object that can read either
   ** from the keyboard (in case args.length == 0) or, otherwise, from the
   ** file whose name is args[0].
   */
   private static void establishScanner(String[] args) {
      if (args.length == 0) {
         input = new Scanner(System.in);
         echo = false; 
      }
      else {
         try {
            String fileName = args[0];
            input = new Scanner(new File(fileName));
            echo = true;
         }
         catch (FileNotFoundException e) {
            e.printStackTrace();
            System.out.println("\nProgram aborting");
            System.exit(0);
         }
      }
   }

}