title: How to use other class files effectively?
body: <p>When does a good programmer know to make a new class file in their games/applications? I've made some small(ish) games and applications with up to 20,000 lines of code in just 1 class file - is this bad practice? The games/applications I make run just fun for what they do and throughout development I've failed to find a reason to make any new class files.</p>
  
  <p>Could I potentially make a fully fledged video game with 100,000+ lines of code in just 1 class file?</p>
  
  <p>In terms of programming languages, I frequently use C# but I've found myself testing about in Java, C++, and Python, always stuck at the same problem. I read through all sorts of source code that has <em>hundreds</em> of class files with just a few lines of code in them - I never understand the point?</p>