RoboCommunity - RoboDuke's Java Lessons

RoboDuke's School of Java - Lesson 6, Chapter 7

RoboDuke — Thu, 14 Feb 2008 04:41:44 GMT

In this lesson we are going to look at inheritance. But first I will tell you a joke from the Robot Kingdom about inheritance. Takes a while but well worth it in the end. Toaster meets Software developer Once upon a time, in a kingdom not far from here, a king summoned two of his advisors for a test. He showed them both a shiny metal box with two slots in the top, a control knob, and a lever. "What do you think this is?" One advisor, an Electrical Engineer, answered first. "It is a toaster," he said. The king asked, "How would you design an embedded computer for it?" The advisor: "Using a four-bit microcontroller, I would write a simple program that reads the darkness knob and quantifies its position to one of 16 shades of darkness, from snow white to coal black. The program would use that darkness level as the index to a 16-element table of initial timer values. Then it would turn on the heating elements and start the timer with the initial value selected from the table. At the end of the time delay, it would turn off the heat and pop up the toast....

RoboDuke's School of Java - Lesson 5, Chapter 6

RoboDuke — Wed, 30 Jan 2008 02:23:15 GMT

Things are going well in the Duke house these days. We had a wonderful holiday season and are now settling down to teaching you more Java. We have come a long ways but you ain’t seen nothing yet! This chapter is so very cool. I promise that ArrayLists are the best thing since sliced bread! Now --- on to our lesson! Download our jar file for lesson 4 from the link below: Lesson5.jar on our Java Group page First – I have decided not to yet post my real cool answer to RoboDuke’s Extra Strength Challenge from the last lesson yet since I have not heard back from enough of you JavaDudes out there with your attempt. To remind you, we were selling robots so that they could take over the world and you were supposed to send me your version of the solution. I will be waiting to see what you can do to help me put a Robot in every household in the world! Let’s look at the other programs you were to write in lesson 4. Here they are. Lesson 4 #1. Now It’s Your Turn Write a program used to determine the smartest robot. Input from...

RoboDuke's Extra Strength Challenge

RoboDuke — Sat, 26 Jan 2008 20:30:21 GMT

RoboDuke’s Extra Strength Challenge Download the jar file located at http://www.vw.vccs.edu/bussci/Wolff/robot/robot.jar . The challenge is to make this a much more robust Java application (using good design as described in chapter 5). Extend this example to keep track of how many robots were sold for each type of robot in each of the individual stores. Keep the store name also. Assume different robots can be sold in different sets of stores (ex. RoboPets are sold in BestBuy in San Diego and Target in Phoenix but Robosapiens are sold only in Walmart in Seattle). When you are done, add a thread to the forum indicating that you are submitting an entry and send your jar file for the entry to Diane Wolff at dwolff@vw.vccs.edu. Tell her RoboDuke sent you!!! Entry submission closes February 11th. First prize will be a very cool t-shirt. Diane will post the best answers to the forum, and you can become famous!!! Contest Rules and Regulations: Promotion. Capable Networks LLC ("Capable Networks") wants to give the opportunity for members of the RoboCommunity website to win various prizes - specifically a WowWee T-shirt - as part of the "RoboDuke's Extra Strength Challenge” contest / promotion. Prizes. These promotional...

RoboDuke's School of Java - Lesson 4, Chapter 5

RoboDuke — Mon, 14 Jan 2008 03:38:14 GMT

So---are you ready for more Java?? If you have forgotten (how could you?? You had better not – it will be on the quiz!!) I am RoboDuke, the Javarian. We finally are putting a lot of the ideas together and developing programs that have some substance. In this lesson, we will review the constructs that we actually have been using in our programs already (you cannot develop a significant application without them) and will look at extra-strength methods. We will also discuss how to use solid design in your program development so that your Robot-friends will not laugh at your coding. First – a warning. If you see any of these dialog boxes pop up during lesson 4, DO NOT --- I repeat DO NOT contact me! I may be a Javarian but I cannot perform miracles!!! Now --- on to our lesson! Download our jar file for lesson 4 from the link below: http://www.robocommunity.com/download/12500/Lesson4.jar/ Let’s look first at the package named answerslesson3 . The movie to watch explaining these answers is at http://www.vw.vccs.edu/bussci/Wolff/robot/answers_l3/answers_l3.html . The code is filled in for the Harvest.java and HarvestDriver.java programs. Yours should be similar. Note the two different versions for the netCost() method (remember...

RoboDuke's School of Java - Lesson 3, Chapter 4

RoboDuke — Fri, 28 Dec 2007 04:06:32 GMT

And on with even more of my Java lessons. If you have forgotten (how could you??) I am RoboDuke, the Javarian. In this lesson, we will come down to ground level as we concentrate on methods, methods, and more methods! But before we do that, how about a good Java joke? What would Juliet have said if she had been a Java programmer? Romeo romeo = new Romeo(); And a definition you can use in this lesson: PROGRAM ( pro’-gram ) – [n] A magic spell cast over a computer allowing it to turn one’s input into error messages ---- or [vi] to engage in a pastime similar to banging one’s head against the wall, but with fewer opportunities for reward. Now --- on to our lesson! Download our jar file for lesson 3 from the link below: http://www.vw.vccs.edu/bussci/Wolff/robot/lesson3.jar or From our Java group download page ! Let’s look first at the package named answerslesson2 . In Lesson 2, you completed a number of programs (you did complete them, didn’t you??) The first one was Ex4Expressions.java . Look at the solution and see if you have any questions. That one was not too bad! Now, how about GuessingGame.java . More...

Java Quick Tip: "Problems" with the Scanner Class

RoboDuke — Sat, 15 Dec 2007 15:58:30 GMT

Sun added the Scanner class in the JDK5.0 version. They did not write all of the methods the way I would have (but who asked me??). There are some quirks to making it work correctly. The problem occurs when reading text input from the keyboard and whether the text has a space in it or not. In the answer for the StockDriver from module 2, note the code // ask for the Customer ID and store the answer in the variable named custNum System.out.println(" What is the customer's id? "); int custNum = scan.nextInt(); scan.nextLine(); // used to make the scanner class behave correctly // ask for the name of the stock.Store the answer in the variable named type System.out.println(" What is the name of the stock? "); String type = scan.nextLine(); In the third line, you see an extra scan.nextLine() . Comment this out and run the program. You will get the following Console output: What is the customer's id? 44 What is the name of the stock? How many shares do you have? Note that it did not wait for the answer to the second prompt before making the third one. You could try using scan.next() ; instead...