4-constants.md

Constants

This Go code demonstrates the use of constants, basic arithmetic operations, and a function from the math package. Let's go through each part of the code:

package main

import (
	"fmt"
	"math"
)

// Declare a constant 's' with type string and initialize it with the value "constant"
const s string = "constant"

func main() {
	// Print the value of the constant 's'
	fmt.Println(s)

	// Declare a constant 'n' and initialize it with the value 500000000
	const n = 500000000

	// Declare a constant 'd' and initialize it with the result of the expression 3e20 / n
	const d = 3e20 / n
	fmt.Println(d)

	// Print the value of 'd' after converting it to int64
	fmt.Println(int64(d))

	// Print the result of the sine function applied to 'n' from the math package
	fmt.Println(math.Sin(n))
}

When you run this Go program, it will output the values of the constants and the result of the mathematical operations to the console.

The output should be something like:

constant
6e+11
600000000000
-0.28470407323754404

Explanation:

1. const s string = "constant": Declares a constant named s of type string and initializes it with the value "constant". Constants in Go are similar to variables but cannot be reassigned after their initial declaration.

2. fmt.Println(s): Prints the value of the constant s to the console.

3. const n = 500000000: Declares a constant named n and initializes it with the value 500000000.

4. const d = 3e20 / n: Declares a constant named d and initializes it with the result of the expression 3e20 / n. The constant d is a floating-point number.

5. fmt.Println(d): Prints the value of the constant d to the console.

6. fmt.Println(int64(d)): Prints the value of d after converting it to an int64. This conversion is necessary because d is a floating-point number, and math.Sin expects an argument of type float64 or float32.

7. fmt.Println(math.Sin(n)): Prints the result of the sine function applied to the constant n using the Sin function from the math package.