Go by Example: Constants

Go supports constants of character, string, boolean, and numeric values.
	`package main`
	`import ( "fmt" "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 conversion.	`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

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