10. Variables

Naming memory locations

What are Variables?

Variables are named memory locations, that are used to refer to data in our program. General format for variable is Go is: var name type = expression

Variable names must start with letter and can contain letter and number.

Declaring variables

Variables are declared using varkeyword. Before using variables, they need to be declared. For declaring variables:

  • Use the var keyword.

  • Write a variable name.

  • Write the variable type.

  • Optionally, assign value using equals =

main.go
func main() {
var s string
s = "sumit"
var i, j, k int
}

Multiple variables of same type can be declared using comma separation in name. All declared variables should be used.Variable name can not be reserved keywords.

keywords
break default func
interface select case
defer go map
struct chan else
goto package switch
const fallthrough if
range type continue
for import return
var

Short variable declaration

Short variable declaration may be used to declare and initialize local variables.It takes the form name := expression.Below declarations are one and the same

main.go
func main() {
var s string
s = "hello, world!"
t := "hello, world!"
var i int
i = 42
j := 42
}

Variable Scope

Variables are visible only with the scope they are declared. We can access the variable so long as it’s in scope, but once a variable is no longer in scope, attempts to access it will report an error. Scope is defined by braces {}

From the Docs