Proof and problem solving (It's not always taught in its own course). These assumptions about this code lead to these conclusions about its validity. If you can

Proof and problem solving (It's not always taught in its own course). These assumptions about this code lead to these conclusions about its validity. If you can't prove your code works (to a human level of proof, not a machine's), why do you think it won't break? The skills of writing a simple proof (break it down so that each logical component is clear) is the same skill as writing clean and testable code.