Now that we have some background on what types are, we can talk about what variables are and how we make and use them. A variable is a named value (like a constant) with the added feature that it can change during the running of a program. If we’re working with a value in various places in our program, we can store that value in a variable to easily access it later.
Variables are defined with the var
keyword and two pieces of information: the name that we will use to refer to them and the type of data stored in the variable. Since variables can be updated we don’t even need to assign a value initially. Here’s a couple of variable definitions:
var lengthOfSong uint16 var isMusicOver bool var songRating float32
Above, we created three variables:
- An unsigned 16-bit integer called
lengthOfSong
. - A boolean value called
isMusicOver
. - A 32-bit float called
songRating
.
Notice that our variable names also follow the same naming convention of constants, using camelCase with a descriptive name.
Instructions
Create a variable called jellybeanCounter
, that will store the number of jellybeans in a jar. Give it a type of int8
.
Successfully doing this will result in an error! We’ll talk more about errors in Go and how to read them in the next exercise, so continue when you’re ready.