Helping people learn Java

Question

Hello,
I am just about to go into my third year of a Applied Computing degree at dundee university. Over the summer I have been part of a project to develop an e-learning course for people that have not used Java before.
I was really wondering if it would be possable for the people in this forum to have a quick play about with a small online tutorial I have been working on and give me any feedback (good or bad) on it.
You can find it at
http://vegeta.computing.dundee.ac.uk/t22/jq/text.asp?id=1
Javascript is required

Answer 1

This was the first example I got.
private float average3(int a, int b, int c)
     double sum;
     sum = a+b+c;
     sum = sum/3.0;
     return(sum);
}Ok, apart from the obvious error of calling the average a sum, I have the following comments:
Whatever your personal choice of {} placement, if you are giving a tutorial, then you should be encouraging the use of the java coding standards (if you don't know what they are, then you shouldn't even be involved in teaching others.
The use of a, b, c as parameter names should again be frowned upon (but I guess in this instance they would be excusable)
The declaration of a variable on one line and its initialisation on another line, while may seem like a correct verbose method of teaching, is actually enforcing bad habits for the future. If a variable can be initialised where it is declared, then it should be....
        double sum;
     sum = a+b+c;
// Why notNow we come to a complete bug in the code. You are declaring sum (I have already given out about the name of that variable, so I won't go into it again) as a double, and you are returning a float as stipulated by the functional specification. Yet you don't cast it to a float... This code won't even compile.
Correct code would include:
    private float average3(int first, int second, int third) {
        return (first + second + third) / 3.0f;
    }or alternatively:
    private float average3(int first, int second, int third) {
        return (float) ((first + second + third) / 3.0);
    }I would suggest that you test any code snippets that you intend to use as teaching aids.