Go Packages and Readme

Author: Rajeev Kumar Singh

12-packages/app/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"github.com/callicoder/golang-tutorials/12-packages/numbers"
+	"github.com/callicoder/golang-tutorials/12-packages/strings"
+	str "strings"
+)
+
+func main() {
+	fmt.Println(strings.WelcomeText)
+	fmt.Println(strings.Reverse("rajeev"))
+	fmt.Println(numbers.IsPrime(9))
+	fmt.Println(str.Contains("Hello, World", "Wo"))
+}

12-packages/numbers/prime.go

@@ -0,0 +1,14 @@
+package numbers
+
+import "math"
+
+// Checks if a number is prime or not
+func IsPrime(num int) bool {
+    for i := 2; i <= int(math.Floor(math.Sqrt(float64(num)))); i++ {
+        if num%i == 0 {
+            return false
+        }
+	}
+	
+    return num > 1
+}

12-packages/strings/constants.go

@@ -0,0 +1,3 @@
+package strings
+
+var WelcomeText = "Hello, World"

12-packages/strings/reverse.go

@@ -0,0 +1,14 @@
+package strings
+
+// Reverses a string
+/*
+	Since strings in Go are immutable, we first convert the string to a mutable array of runes ([]rune), 
+	perform the reverse operation on that, and then re-cast to a string.
+*/
+func Reverse(s string) string {
+	chars := []rune(s)
+	for i, j := 0, len(chars)-1; i < j; i, j = i+1, j-1 {
+		chars[i], chars[j] = chars[j], chars[i]
+	}
+	return string(chars)
+}

Readme.md

@@ -1,5 +1,7 @@
 ## Golang Tutorials
 
+0. [Golang Installation, Setup, GOPATH, and Go Workspace](https://www.callicoder.com/golang-installation-setup-gopath-workspace/)
+
 1. [Writing your first Go program](https://www.callicoder.com/golang-introduction-hello-world/)
 
 2. [Golang Variables, Zero Values, and Type inference](https://www.callicoder.com/golang-variables-zero-values-type-inference/)