import java.util.Scanner;

/* Java program that computes (and reports) body mass index (BMI) values for
** a particular height and the weights within a range beginning at some 
** specified lower bound up to some specified upper bound, and increasing by 
** some specified interval.
**
** This version improves upon the previous one by using calls to
** System.out.printf() to produce as output a table whose columns 
** are nicely aligned. 
**
** The main purposes are to illustrate the use of Java's for-loop construct
** and reading input using a Scanner object.
*/

public class BMICalculatorApp6 {

   private static Scanner keyboard; // for reading input from the keyboard

   private static int height;       // height in inches (input)
   private static int lowWeight;    // lower bound weight (in pounds) (input)
   private static int highWeight;   // uppper bound weight (in pounds) (input)
   private static int weightGap;    // gap between weights (in pounds) (input)
   private static double bmi;       // BMI value (output)

   private static int weight;     // weight in pounds (loop control variable)

   public static void main(String[] args)
   {
      // Create a Scanner object and enable it to read input entered at the keyboard.
      keyboard = new Scanner(System.in);

      System.out.print("Enter height (in inches): ");

      // Read input value entered at the keyboard, interpreting it as a value of
      // type int; then place that value into the 'height' input variable.
      height = keyboard.nextInt();

      System.out.print("Enter bottom weight (in pounds): ");
      lowWeight = keyboard.nextInt();

      System.out.print("Enter top weight (in pounds): ");
      highWeight = keyboard.nextInt();

      System.out.print("Enter weight gap (in pounds): ");
      weightGap = keyboard.nextInt();

      printColHeadings();

      for (weight = lowWeight; weight <= highWeight; weight = weight + weightGap) {
         reportBMIValue();
      }
   }

   /* Reports the BMI value corresponding to the values in the global variables
   ** 'height' and 'weight'.
   */
   private static void reportBMIValue() {

      computeBMI();

      // Print the values of 'height' and 'weight', each right-justified in a 
      // field of width 6 followed by a space.  Then print the value of 'bmi'
      // in a field of width five with two digits after the decimal point.
      // Then print a newline character (to skip to next line).
      System.out.printf("%6d %6d %5.2f\n", height, weight, bmi);
   }


   /* Assigns to global variable 'bmi' the BMI value computed from the values
   ** in global variables 'height' and 'weight'.
   */
   private static void computeBMI()
   {
      // Conversion factor needed to convert result of BMI formula when height
      // and weight are measured in inches and pounds rather than in meters
      // and kilograms, respectively.
      final int UNIT_CONVERSION_FACTOR = 703;
   
      bmi = UNIT_CONVERSION_FACTOR * ((double)weight / (height * height));
   }

   private static void printColHeadings() {
      System.out.printf("%6s %6s %3s\n", "Height", "Weight", "BMI");
      System.out.println("------ ------ -------");
   }

}