Go by Example: Constants

Go supports constants of character, string, boolean, and numeric values.
	package main
	import "fmt" import "math"
`const` declares a constant value.	const s string = "constant"
	func main() { fmt.Println(s)
A `const` statement can appear anywhere a `var` statement can.	const n = 500000000
Constant expressions perform arithmetic with arbitrary precision.	const d = 3e20 / n fmt.Println(d)
A numeric constant has no type until it’s given one, such as by an explicit cast.	fmt.Println(int64(d))
A number can be given a type by using it in a context that requires one, such as a variable assignment or function call. For example, here `math.Sin` expects a `float64`.	fmt.Println(math.Sin(n)) }

$ go run constant.go 
constant
6e+11
600000000000
-0.28470407323754404

Next example: For.