GCD and LCD added. (#214)

# Describe Request

Greatest Common Divisor (GCD) and Least Common Multiple (LCM) functions
are added.

# Change Type

New feature.

helper/README.md

@@ -47,12 +47,14 @@ The information provided on this project is strictly for informational purposes
 - [func Field\[T, S any\]\(c \<\-chan \*S, name string\) \(\<\-chan T, error\)](<#Field>)
 - [func Filter\[T any\]\(c \<\-chan T, p func\(T\) bool\) \<\-chan T](<#Filter>)
 - [func First\[T any\]\(c \<\-chan T, count int\) \<\-chan T](<#First>)
+- [func Gcd\(values ...int\) int](<#Gcd>)
 - [func Head\[T Number\]\(c \<\-chan T, count int\) \<\-chan T](<#Head>)
 - [func IncrementBy\[T Number\]\(c \<\-chan T, i T\) \<\-chan T](<#IncrementBy>)
 - [func JSONToChan\[T any\]\(r io.Reader\) \<\-chan T](<#JSONToChan>)
 - [func KeepNegatives\[T Number\]\(c \<\-chan T\) \<\-chan T](<#KeepNegatives>)
 - [func KeepPositives\[T Number\]\(c \<\-chan T\) \<\-chan T](<#KeepPositives>)
 - [func Last\[T any\]\(c \<\-chan T, count int\) \<\-chan T](<#Last>)
+- [func Lcm\(values ...int\) int](<#Lcm>)
 - [func Map\[F, T any\]\(c \<\-chan F, f func\(F\) T\) \<\-chan T](<#Map>)
 - [func MapWithPrevious\[F, T any\]\(c \<\-chan F, f func\(T, F\) T, previous T\) \<\-chan T](<#MapWithPrevious>)
 - [func Multiply\[T Number\]\(ac, bc \<\-chan T\) \<\-chan T](<#Multiply>)
@@ -479,6 +481,15 @@ func First[T any](c <-chan T, count int) <-chan T
 
 First takes a channel of values and returns a new channel containing the first N values.
 
+<a name="Gcd"></a>
+## func [Gcd](<https://github.com/cinar/indicator/blob/master/helper/gcd.go#L8>)
+
+```go
+func Gcd(values ...int) int
+```
+
+Gcd calculates the Greatest Common Divisor of the given numbers.
+
 <a name="Head"></a>
 ## func [Head](<https://github.com/cinar/indicator/blob/master/helper/head.go#L16>)
 
@@ -567,6 +578,15 @@ func Last[T any](c <-chan T, count int) <-chan T
 
 Last takes a channel of values and returns a new channel containing the last N values.
 
+<a name="Lcm"></a>
+## func [Lcm](<https://github.com/cinar/indicator/blob/master/helper/lcm.go#L8>)
+
+```go
+func Lcm(values ...int) int
+```
+
+Lcm calculates the Least Common Multiple of the given numbers.
+
 <a name="Map"></a>
 ## func [Map](<https://github.com/cinar/indicator/blob/master/helper/map.go#L17>)
 

helper/gcd.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2021-2024 Onur Cinar.
+// The source code is provided under GNU AGPLv3 License.
+// https://github.com/cinar/indicator
+
+package helper
+
+// Gcd calculates the Greatest Common Divisor of the given numbers.
+func Gcd(values ...int) int {
+	gcd := values[0]
+
+	for i := 1; i < len(values); i++ {
+		value := values[i]
+
+		for value > 0 {
+			gcd, value = value, gcd%value
+		}
+
+		if gcd == 1 {
+			break
+		}
+	}
+
+	return gcd
+}

helper/gcd_test.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2021-2024 Onur Cinar.
+// The source code is provided under GNU AGPLv3 License.
+// https://github.com/cinar/indicator
+
+package helper_test
+
+import (
+	"testing"
+
+	"github.com/cinar/indicator/v2/helper"
+)
+
+func TestGcdWithTwoValues(t *testing.T) {
+	actual := helper.Gcd(1220, 512)
+	expected := 4
+
+	if actual != expected {
+		t.Fatalf("actual %d expected %d", actual, expected)
+	}
+}
+
+func TestGcdWithThreeValues(t *testing.T) {
+	actual := helper.Gcd(1, 2, 5)
+	expected := 1
+
+	if actual != expected {
+		t.Fatalf("actual %d expected %d", actual, expected)
+	}
+}
+
+func TestGcdWithFourValues(t *testing.T) {
+	actual := helper.Gcd(2, 4, 6, 12)
+	expected := 2
+
+	if actual != expected {
+		t.Fatalf("actual %d expected %d", actual, expected)
+	}
+}

helper/lcm.go

@@ -0,0 +1,16 @@
+// Copyright (c) 2021-2024 Onur Cinar.
+// The source code is provided under GNU AGPLv3 License.
+// https://github.com/cinar/indicator
+
+package helper
+
+// Lcm calculates the Least Common Multiple of the given numbers.
+func Lcm(values ...int) int {
+	lcm := values[0]
+
+	for i := 1; i < len(values); i++ {
+		lcm = (values[i] * lcm) / Gcd(values[i], lcm)
+	}
+
+	return lcm
+}

helper/lcm_test.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2021-2024 Onur Cinar.
+// The source code is provided under GNU AGPLv3 License.
+// https://github.com/cinar/indicator
+
+package helper_test
+
+import (
+	"testing"
+
+	"github.com/cinar/indicator/v2/helper"
+)
+
+func TestLcmWithTwoValues(t *testing.T) {
+	actual := helper.Lcm(18, 32)
+	expected := 288
+
+	if actual != expected {
+		t.Fatalf("actual %d expected %d", actual, expected)
+	}
+}
+
+func TestLcmWithFourValues(t *testing.T) {
+	actual := helper.Lcm(1, 2, 8, 6)
+	expected := 24
+
+	if actual != expected {
+		t.Fatalf("actual %d expected %d", actual, expected)
+	}
+}
+
+func TestLcmWithFiveValues(t *testing.T) {
+	actual := helper.Lcm(2, 7, 3, 9, 8)
+	expected := 504
+
+	if actual != expected {
+		t.Fatalf("actual %d expected %d", actual, expected)
+	}
+}