Now we have completed the basics of using packages, let’s move on to comments.
Before Commenting…
“Don’t comment bad code — rewrite it.” — Brian W. Kernighan and P. J. Plaugher.
Try to make code as clean and self-explanatory before adding comments. They should be the icing on the cake rather than the filling!
Comments are useful for:
- Explaining what the code does & why something was done a certain way
- Outlining important or fragile blocks of code, which require extra care
- Noting down what we need to do when we are writing the code
- Disabling code without deleting it
- Adding information to be picked up by the
go doc
tool (more on that later)
Types
There are two types of comments in Go.
Line Comments
Line comments start with a //
and the rest of the line is ignored by the compiler.
// This entire line is ignored by the compiler // fmt.Println("Does NOT print") fmt.Println("This gets printed!") // This part gets ignored
Note how you can add a //
after the code, without affecting it.
Block Comments
Block comments can span multiple lines.
They start with a /*
and end with a */
, enveloping everything inside:
/* This is ignored. This is also ignored. fmt.Println("This WON'T print!") */
In the example above we’ve commented out all three lines using a block comment.
Now let’s use some comments in our own code!
Instructions
Use a line comment, //
, to comment out Are we racing or coding?
Use a block comment, /* */
to comment out the first TWO fmt.Println()
statements.
Run the program using the command line.