Letting Go Infer A Variable's Type

You do not always have to write the type in a var declaration. If you provide a starting value, Go can determine the variable’s type from that value. The variable still has fixed type after it is declared in The Golang Official Documentation

package main
 
import "fmt"
 
func main() {
	var count = 10
	fmt.Printf("%v %T\n", count, count)
}

If you’ll run this with go run main.go, then you’ll get the output 10 int

In var count = 10, the untyped integer 10 gives count the default type int. The program prints both the value and the type: %v shows 10 and %T shows int. Its convenient to not write the type but it doesn’t mean that count can later turn into a string or another type