Golang Constants Comprehension

Introduction

This lab aims to test your understanding of constants in Golang.

Skills Graph

Constants

The problem to be solved is to demonstrate the use of constants in Golang for character, string, boolean, and numeric values.

The lab has the following requirements:

• Use the const keyword to declare a constant value.
• Constants should be of character, string, boolean, and numeric values.
• A constant statement can appear anywhere a var statement can.
• Demonstrate that constant expressions perform arithmetic with arbitrary precision.
• A numeric constant has no type until it's given one, such as by an explicit conversion.
• A number can be given a type by using it in a context that requires one, such as a variable assignment or function call.

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

There is the full code below:

// 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))
}

Summary

In this lab, you learned how to declare and use constants in Golang. Constants can be of character, string, boolean, and numeric values. Constant expressions perform arithmetic with arbitrary precision. A numeric constant has no type until it's given one, such as by an explicit conversion.