110CT: Lecture 9a Portfolio Questions 2007-8

 
 
Portfolio Requirements
These exercises are mostly based on material covered in a range of previous lectures. There are a couple of new concepts introduced though.

 

  • 9a.1: no project

    Re-run the 'object types' demo from CUOnline.

    1. At the end of the sequence, what colour would be the result returned by objectA.getColor(); Explain, carefully, why this is the case. Ensure you use the OOP terms 'object', 'instantiation' (or 'instance'), 'attribute' and 'state'.
    2. Go back to your answer to portfolio 2.3. Explain why the question asked you to set up a new attribute window2 and not just re-use window. If you are not sure, alter your project so it DOES re-use window and then change the colour of the right window to, say, blue.

    In your portfolio include answers to both questions.

    (not from Barnes and Kolling)

    •  

  • 9a.2: no project

    In portfolio 5.6 you were asked to produce a logical expression which evaluated to true/false in specified situations. As a truth table this question can be expressed as follow:

    abrequire
    TTF
    TFT
    FTT
    FFF

    Some students submitted !(a == b) as a solution. Create a truth table to check whether this is a correct answer. Is it correct?

    In your portfolio include your truth table and an answer.

    (not from Barnes and Kolling)

    •  

  • 9a.3: no project

    Complete CU BlueJ tutorial 7 about creating a new project.

    Create a new project containing a single new class, called Modifier. It has no attributes. Create a method in this class called charToUpper(). This should use the signature (heading) of:

    public char charToUpper(char ch)

    and should do the following. It should take in, as a parameter 'ch', a valid alphabetic character, upper or lower-case. It should return, as its result, the character 'ch' converted into the equivalent upper-case character. If 'ch' is not alphabetic then return it unconverted.

    Character values
    Don't forget, a char is written in single-quotes, eg 'x'.

    Each character has a numeric value: A-Z are 65-90 and a-z are 97-122. You can convert from char form into the equivalent numeric code using a 'cast' eg (int) ch; and, in reverse, from an integer to a char using, for example, (char) value;

    In addition to the conversion, to assist in testing the method, it should also print out the character parameter value coming in and the character produced as the method's result.

    Create a Modifier object and run its charToUpper method. Test it with an appropriate set of character data.

    In your portfolio, provide a printout of your class' code and a table showing the values used to test your work (both input value and the expected output).

    (not from Barnes and Kolling)

 

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Last modified: 12 Dec 2007
Webpage: © Lisa Payne, Coventry University, 2006-7
Exercises and projects: © Barnes and Kolling