prime

README

golang-prime

This package provides some functions for working with prime numbers.

Example

package main

import (
	"fmt"

	prime "github.com/theTardigrade/golang-prime"
)

func main() {
	var magicNumber int64 = 3

	fmt.Println(prime.Is(magicNumber))   // true
	fmt.Println(prime.Next(magicNumber)) // 5, true
	fmt.Println(prime.Prev(magicNumber)) // 2, true

	fmt.Println("*****")

	magicNumber = 120

	fmt.Println(prime.Is(magicNumber))   // false
	fmt.Println(prime.Next(magicNumber)) // 127, true
	fmt.Println(prime.Prev(magicNumber)) // 113, true

	fmt.Println("*****")

	magicNumber = 2

	fmt.Println(prime.Is(magicNumber))   // true
	fmt.Println(prime.Next(magicNumber)) // 3, true
	fmt.Println(prime.Prev(magicNumber)) // 0, false

	fmt.Println("*****")

	magicNumber = 1_000_000_000_000

	fmt.Println(prime.Is(magicNumber))   // false
	fmt.Println(prime.Next(magicNumber)) // 1000000000001, true
	fmt.Println(prime.Prev(magicNumber)) // 999999999997, true
}

Support

If you use this package, or find any value in it, please consider donating:

Documentation

Index

• func BigIs(bigN *big.Int) bool
• func BigIsAdditive(bigN *big.Int) bool
• func BigNext(bigN *big.Int) (bigPrime *big.Int)
• func BigNextAdditive(bigN *big.Int) (bigAdditivePrime *big.Int)
• func BigPrev(bigN *big.Int) (bigPrime *big.Int, exists bool)
• func BigPrevAdditive(bigN *big.Int) (bigAdditivePrime *big.Int, exists bool)
• func Is(n int64) bool
• func IsAdditive(n int64) bool
• func Next(n int64) (prime int64, exists bool)
• func NextAdditive(n int64) (additivePrime int64, exists bool)
• func Prev(n int64) (prime int64, exists bool)
• func PrevAdditive(n int64) (additivePrime int64, exists bool)

Functions

func BigIs

func BigIs(bigN *big.Int) bool

BigIs determines whether a given number of arbitrary size is prime.

func BigIsAdditive

func BigIsAdditive(bigN *big.Int) bool

BigIsAdditive determines whether a given number of arbitrary size is additively prime. This means that the number itself must be prime and the sum of its decimal digits must also be prime.

func BigNext

func BigNext(bigN *big.Int) (bigPrime *big.Int)

BigNext returns the next prime number after a given number of arbitrary size.

func BigNextAdditive

func BigNextAdditive(bigN *big.Int) (bigAdditivePrime *big.Int)

BigNextAdditive returns the next additive prime number after a given number of arbitrary size.

func BigPrev

func BigPrev(bigN *big.Int) (bigPrime *big.Int, exists bool)

BigPrev returns the previous prime number before a given number of arbitrary size. It also returns a boolean value that is set to false if no prime number exists before the given number.

func BigPrevAdditive

func BigPrevAdditive(bigN *big.Int) (bigAdditivePrime *big.Int, exists bool)

BigPrevAdditive returns the previous additive prime number before a given number of arbitrary size. It also returns a boolean value that is set to false if no additive prime number exists before the given number.

func Is

func Is(n int64) bool

Is determines whether a given 64-bit number is prime.

func IsAdditive

func IsAdditive(n int64) bool

IsAdditive determines whether a given 64-bit number is additively prime. This means that the number itself must be prime and the sum of its decimal digits must also be prime.

func Next

func Next(n int64) (prime int64, exists bool)

Next returns the next prime number after a given 64-bit number. It also returns a boolean value that is set to false if no prime number exists after the given number (not because there is no such number in the mathematical set of integers, but rather because there is no such number that can be represented by a 64-bit integer in Go).

func NextAdditive

func NextAdditive(n int64) (additivePrime int64, exists bool)

NextAdditive returns the next additive prime number after a given 64-bit number. It also returns a boolean value that is set to false if no additive prime number exists after the given number (not because there is no such number in the mathematical set of integers, but rather because there is no such number that can be represented by a 64-bit integer in Go).

func Prev

func Prev(n int64) (prime int64, exists bool)

Prev returns the previous prime number before a given 64-bit number. It also returns a boolean value that is set to false if no prime number exists before the given number.

func PrevAdditive

func PrevAdditive(n int64) (additivePrime int64, exists bool)

Prev returns the previous additive prime number before a given 64-bit number. It also returns a boolean value that is set to false if no additive prime number exists before the given number.