ITEC 120 2008fall aaray, ejderrick, ibarland, jmdymacek

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lab06b
lab06b

P4.17: Write a program that transforms numbers 1,2,…,12 into the corresponding month names "January", "February", …, "December".

Hint: Make one very long string "January February March …" in which you add spaces such that each month has the same length. Then use substring to extract the month you want. Implement a class Month whose constructor parameter is the month number and whose getName method returns the month name.
For an extra challenge, make sure you don't return any spaces at the end of the month name — find a String method which will remove the trailing spaces.
Do not use an “if” statement.

public class MonthTester {
  public static void main( String[] args ) {
    Month m1 = new Month(1);
    System.out.println( "Expect \"January\": " + m1.getName() );

    // Add at least two more tests here.
    }
  }

Super challenge: add a second method to class Month: one named getDays which returns how many days the Month has.

• One 'parallel' approach would be to have one big number 31283130…3031, and then use Math.pow(100,monthnum), %, and / to extract the digits you want. However, Java's int can't store 24 digits (nor can its long type).
• You can instead compress the data by storing the number of days of each month beyond 28: 3032…23. A long can store 12 digits.
  This is a weird solution, but it does give you experience using % and /.
• Another approach would be to have a String of 24 digits (not a number at all), pull out the 2-digit substring, and then convert the String into an int. This requires calling Integer.parseInt. For example, Integer.parseInt("234") returns 234.
• Both these approaches are unnatural. (encoding twelve separate numbers as a single long or String). A natural solution would keep a table (an array) of twelve numbers, and simply look up the number-of-days in that array. We won't cover arrays for several weeks yet, but we will eventually!

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©2008, Ian Barland, Radford University Last modified 2008.Nov.02 (Sun)

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