code reorganization

Author: Rajeev Kumar Singh

07-packages/app/main.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"fmt"
+	"github.com/callicoder/golang-tutorials/07-packages/numbers"
+	"github.com/callicoder/golang-tutorials/07-packages/strings"
+	"github.com/callicoder/golang-tutorials/07-packages/strings/greetings" // Importing a nested package
+	str "strings"	// Package Alias
+)
+
+func main() {
+	fmt.Println(numbers.IsPrime(19))
+
+	fmt.Println(greetings.WelcomeText)
+
+	fmt.Println(strings.Reverse("callicoder"))
+
+	fmt.Println(str.Count("Go is Awesome. I love Go", "Go"))
+}

12-packages/numbers/prime.go renamed to 07-packages/numbers/prime.go

@@ -0,0 +1,13 @@
+// Nested Package
+package greetings
+
+// Exported
+const WelcomeText = "Hello, World to Golang"
+const MorningText = "Good Morning"
+const EveningText = "Good Evening"
+
+// Not exported (only visible inside the `greetings` package)
+var loremIpsumText = `Lorem ipsum dolor sit amet, consectetur adipiscing elit, 
+sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad 
+minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea 
+commodo consequat.`

07-packages/strings/greetings/texts.go

@@ -6,9 +6,7 @@ package strings
 	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)
+	runes := []rune(s)
+	reversedRunes := reverseRunes(runes)
+	return string(reversedRunes)
 }

12-packages/strings/reverse.go renamed to 07-packages/strings/reverse.go

@@ -0,0 +1,10 @@
+package strings
+
+// Reverses an array of runes
+// This function is not exported (It is only visible inside the `strings` package)
+func reverseRunes(r []rune) []rune {
+	for i, j := 0, len(r)-1; i < j; i, j = i+1, j-1 {
+		r[i], r[j] = r[j], r[i]
+	}
+	return r
+}