Let's explore two ways we can reuse existing code. After writing our code to replace strings in a ZIP file full of text files, we are later contracted to scale all the images in a ZIP file to 640 x 480. It looks like we could use a very similar paradigm to what we used in ZipReplace. Our first impulse might be to save a copy of that file and change the find_replace method to scale_image or something similar.
But, that's suboptimal. What if someday we want to change the unzip and zip methods to also open TAR files? Or maybe we'll want to use a guaranteed unique directory name for temporary files. In either case, we'd have to change it in two different places!
We'll start by demonstrating an inheritance-based solution to this problem. ...
