Comments

We'll talk more about methods shortly, but 0:00 I want to take a moment to tell you about another important feature of Ruby. 0:02 Most programming languages support comments, snippets of text that you can 0:06 insert into your code that are meant for humans to read, not the computer. 0:10 Ruby supports comments, too. 0:14 Let's suppose you have some code and 0:16 you think it won't be immediately obvious to other developers what it does. 0:18 You can't just start typing an explanation. 0:21 Ruby will think the text is part of your program and 0:25 try to run it, which won't work. 0:27 Instead, you need to mark the text as something that shouldn't be run. 0:30 If you insert a pound sign, or hash mark, into your code and 0:34 it's not part of a string, 0:37 Ruby will ignore all the text from the pound sign to the end of the line. 0:39 You can do this on a line by itself, or 0:43 you can do it at the end of a line of code. 0:45 You can use this to leave useful comments throughout your code. 0:49 Any time where you write some code where the meaning isn't immediately obvious. 0:53 First you should try to rewrite the code so that it's clear all by itself. 0:57 But if that isn't possible for 1:00 whatever reason, you can add a comment that explains the code. 1:02 So let's add a quick explanation to this line of code here. 1:05 Prints hello world To the terminal. 1:08 Let's save that, and try running it. 1:18 And the first line is ignored because Ruby ignores everything from the pound sign 1:22 to the end of the line. 1:26 Only the second line actually gets run. 1:28 And now whenever you or any other developer looks at this code, 1:30 it will be immediately obvious what it does. 1:33