Helping Kids with Coding For Dummies

Chapter 13

Fixing Problems by Debugging

IN THIS CHAPTER

Finding and reading error messages

Tracking down common bugs

Debugging strategies

Bugs have been causing coders headaches and frustration for decades. Coders spend upwards of 50 percent of their time debugging — fixing errors in their code, and not just writing code! This is part of what makes coding so “hard.” It’s not impossible to figure out — it just takes persistence when the computer is telling you you’re wrong.

You can encounter two different kinds of coding bugs: syntax bugs and semantic bugs. Syntax bugs are ones where you have written something incorrectly. Maybe you spelled a variable wrong, or you forgot a semicolon at the end of your line of code. These bugs are often easy to fix and result in your programming environment displaying an error message to you. Semantic bugs are ones where your logic is incorrect. For example, you’re iterating through a list of five numbers and you try to access the sixth element, or you’re checking to see whether variable1 is less than variable2 in an if-then statement, but you accidentally write variable1 > variable2. These bugs are often harder to find because they require you to ...