package main

import (
	"fmt"
	"math"
)

// Constants are declared like variables, but with the const keyword.
const s string = "constant"

func main() {
	//A constant is a simple unchanging value. Constants can be character, string, boolean, or numeric values.
	fmt.Println(s)

	//Constants can be declared as a group, like variables.
	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 an argument to a function.
	// Here, math.Sin expects a float64, so the untyped constant n is given that type.
	fmt.Println(math.Sin(n))
}