Variables

The var keyword declares a variable with an explicit type: var name type = value. Once age is declared this way, it can only ever hold an int for the rest of its life — that's what being statically typed means in practice.

var age int = 25
fmt.Println(age)

If you give var an initial value, you can actually leave the type out entirely, and Go infers it from that value automatically — var name = "Maya" makes name a string without you writing string anywhere.

var name = "Maya"
fmt.Println(name)

Inside a function, there's an even shorter way to declare a variable: the := short declaration operator. age := 25 declares age and infers its type in a single step — it's equivalent to var age = 25, just shorter to write, and it's the style most idiomatic Go code uses. The one catch is that := only works inside a function body, never at the package level.

age := 25
name := "Maya"
fmt.Println(age, name)

Inside a function, the ____ operator declares a new variable and infers its type from the value on the right, all in one step.

Where can the := short variable declaration be used in Go?

One important gotcha: := always declares a brand-new variable, so using it a second time for the same name in the same scope is a compile error, since there's nothing new left to declare. To change an existing variable's value afterward, use the plain = operator instead, which reassigns without declaring anything.

age := 25
// age := 26   // compile error: no new variables on left side of :=

age = 26       // fine — reassigns the existing variable
fmt.Println(age) // 26

Once a variable has been declared with :=, you can use := again on that same name to change its value later.