[Tutor] Code critique please (OOP strategy)

[Sean 'Shaleh' Perry]

On 31-Dec-2001 Timothy Wilson wrote:
> Hi everyone,
> 
> I've done an object-oriented version of the stock portfolio tracking
> program I assigned to my students
> (http://www.isd197.org/sibley/cs/icp/assignments/portfolio_html). I plan
> to use this for comparison when we introduce OOP after the Winter Break.
> 
> My version is available at http://www.qwerk.org/tim/
> 
> I'd like to get some feedback on the code. I've created two classes
> here, Portfolio and Stock. I'm specifically interested in the way the
> main() function interacts with the class methods. I've got a strange mix
> of program logic stuck in a series of elif statements and in the class
> methods themselves. Something doesn't seem right about it.
> 

In my opinion, constructing a class should never cause the program to stop at a
prompt.  This prevents later use.  If I wanted to make a list of portfolio's
and then give them files to open, I see no way to do this.  In C++ parlance you
have no default constructor.

I am also curious as to why the prices are * 100 every time.  There is no
comment in the code for this.

> Is there a way to create a Menu class that would help?
> 

you could make a menu class or function, but all that would do is move the
code out of main.

What you could do is have each menu choice be a function (or class method) and
have the code do a dictionary lookup -- think symbol table.

options['A'] = addNewStock
options['D'] = deleteStock
...

while not done:
    input = raw_input(prompt)
    try:
        options[input.upper()]()
    except KeyError:
        print "Invalid choice!"