Golang golang-math (snippet)

Go programming example 'golang-math'

golang-math

Golang beginners example: golang-math

package main

import (
    "fmt"
)

func Abs(x int) int {
    if x > 0 {
        return x
    }
    return -x
}

func GreatestCommonDivisor(a, b int) int {
    for a != 0 {
        a, b = b%a, a
    }
    return b
}

func LeastCommonMultiple(a, b int) int {
    return a * b / GreatestCommonDivisor(a, b)
}

func Sqrt(n int64) int64 {
    var t int64
    var b int64
    var r int64
    t = int64(n)
    p := int64(1 << 30)
    for p > t {
        p >>= 2
    }
    for ; p != 0; p >>= 2 {
        b = r | p
        r >>= 1
        if t >= b {
            t -= b
            r |= p
        }
    }
    return int64(r)
}

func Prime(n int) int {
    var primeList = []int{2}
    isPrime := 1
    num := 3
    sqrtNum := 0
    for len(primeList) < n {
        sqrtNum = int(Sqrt(int64(num)))
        for i := 0; i < len(primeList); i++ {
            if num%primeList[i] == 0 {
                isPrime = 0
            }
            if primeList[i] > sqrtNum {
                i = len(primeList)
            }
        }
        if isPrime == 1 {
            primeList = append(primeList, num)
        } else {
            isPrime = 1
        }
        num = num + 2
    }
    return primeList[n-1]
}

func Sum(numbers ...int) int {
    var sum int
    for i := 0; i < len(numbers); i++ {
        sum += numbers[i]
    }
    return sum
}

func main() {
    fmt.Printf("Abs(-3): %v\n", Abs(-3))
    fmt.Printf("GreatestCommonDivisor(6,16): %v\n", GreatestCommonDivisor(6, 16))
    fmt.Printf("LeastCommonMultiple(12,24): %v\n", LeastCommonMultiple(12, 24))
    fmt.Printf("Sqrt(9): %v\n", Sqrt(9))
    fmt.Printf("Prime(15): %v\n", Prime(15))
    fmt.Printf("Sum(3,5,7,9): %v\n", Sum(3, 5, 7, 9))
}

Useful links

• Learn Go: https://golangr.com
• Download Go: https://golang.org