Notes, Thursday, September 27

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Working on Assignment 3

Here are the pieces that were/will be discussed in class this week.

There are three classes CatalogEntry, CatalogNode, and Catalog. Their header files are

And here are implementations of some of the functions and operators.

Computing the number of entries in the catalog: size.cxx.
Making the catalog empty without leaking memory: makeEmpty.cxx.
Inserting an entry into the catalog: operator +=.
Opening and reading from a text file: case 'f'.

Using colors

(This was not explained in class in detail.) Here is how you can add colors to your MovingObject-s.

Add a private variable

int color;

Then in the constructor you can do, e.g.,

color = CDraw::randomLightColor ();

As an example of how to use the enumerated type

enum Color { black, blue, gray, lime, red, white, yellow };

you can give your MovingObject-s a black perimeter this way, in the output operator:

// output
ostream& operator << ( ostream& out, const MovingObject& mo ) 
{
    const int DIAMETER = 50;

    CDraw::setColor (mo.color);
    CDraw::fillCircle (mo.x, mo.y, DIAMETER);

    CDraw::setColor (CDraw::black);
    CDraw::drawCircle (mo.x, mo.y, DIAMETER);

    return out;
}

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3:40 PM, Thursday, December 12, 2002