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hw05
if
nesting, if-else-if

Due ~~Mar.06 (Fri)~~ Mar.18 (Wed).
However I encourage you to finish most or all of it before the break; we'll also have other new topics to keep us busy when we return!

(10pts; if-else) Write class Employee whose constructor takes one input: the employee's hourly wage. Then, write a method calcWeeklyPay which takes in the number of hours worked in a week, and returns how much the employee should be paid. All hours over 40hrs are paid at 1.5× their hourly wage.

Your test driver ¹ (which you write before the rest of the code) should test at least three situations: working less than 40hrs, working exactly 40hrs, and working more than 40hrs.

(10pts) P5.2. Be sure to indent if-else-ifs appropriately!

Note that getDescription should spell out the suit, and should spell out the rank for face cards and aces; however (unlike the book) you can use digits for 2 through 10 (rather than spelling out the rank). You may use the following test class:

import java.util.Scanner;

public class CardPrinter {
  public static void main( String[] args ) {
    Card c1 = new Card("4S");
    Card c2 = new Card("QD");

    // Problem #3: Draw diagram for this point in time.

    System.out.println( "Expect \"4 of spades\", got\"" + c1.getDescription() + "\"." );
    System.out.println( "Expect \"Queen of diamonds\", got\"" + c2.getDescription() + "\"." );
    

    // Now, include the interactive test call (using System.in) from the book:
    System.out.println( "Please enter a card rank and suit (e.g. `4H` or `QD` or `10C`):" );
    Scanner in = new Scanner(System.in);
    String input = in.nextLine();
    Card card = new Card(input);
    System.out.println( input + " is shorthand for the " + card.getDescription() );
    }
  }

You can assume that only legal card-shorthand is entered. (So you can ignore the part of the problem asking you to return "Unknown" as the book states.)

(5pts) Draw a diagram of what memory looks like for CardPrinter after the first two lines of code (at the indicated comment).
Your answer should look similar to exam01, #4b.

(15pts) P5.7: Write a class TresAmigos which contains three Strings, and has methods getFirst, getSecond, and getThird which returns the alphabetically² first, second, and third name respectively. Work carefully, and indent well -- it is easy to get lost in the various cases. Don't wait until the last moment, to start this!

Use nested ifs ³. For example, if ami1,ami2,ami3 are all Strings, your code might contain some lines like:

        if (ami1.compareTo(ami2) < 0)
        {
            if (ami2.compareTo(ami3) < 0)
            {
                // If we reach here, we know ami1 < ami2 < ami3.
            }
            else 
            { 
                // If we reach here, we know ami2 is last (since ami1 < ami2, and ami3 <= ami2.)
            }
        }
        else  // ami2 <= ami1.
        {
           // ... compare ami1 vs ami3, maybe?
        }

(Coloring is for readability only.)

Note that your class TresAmigos should not involve println (or, Scanner). Here is a fairly comprehensive test-class, so you don't need to write any tests yourself. (While we haven't written programs quite like that test-class so far, we're getting close; if you're curious, pore over this code to see how it works, asking your prof or a PI if you have questions.)

BlueJ tip: Make the terminal window active, and then select Options > Clear Screen at method call. This way, every time you call a method, it will erase any old (error) messages.

¹ One question I received: Should the amount paid be printed with exactly two decimal places?
Answer: Don't worry about formatting. calcWeeklyPay should return an amount of money (not a piece of text). The test-driver should check that it's giving the correct number back, but formatting the number in a particular matter is not necessary for a test program. ↩

²Or, as the book calls it, “lexicographically”. See the book's discussion of the String method compareTo. ↩

³Alternately, you are welcome to use if-else-ifs along with &&, ||, !. ↩

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©2009, Ian Barland, Radford University
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hw05 ifnesting, if-else-if

hw05
if
nesting, if-else-if