docs: improve go code formatting and add comments

Go/Concepts/12) slices2.go

@@ -8,7 +8,7 @@ func main() {
 
 	fmt.Println(cars)
 	var index int = 2
-	cars = append(cars[:index], cars[index+1:]...) // remove the element at index 2. :index is from 0 to index-1, [index+1:] is from index+1 to end
+	cars = append(cars[:index], cars[index+1:]...) // remove the element at index 2. :index is from 0 to index-1, [index+1:] is from index+1 to end. We can append both elements as well as a slice. ... is to denote a slice
 	fmt.Println(cars)
 
 }

Go/Concepts/15) if-else.go

@@ -17,8 +17,6 @@ func main() {
 		fmt.Println("Your number is less than 10")
 	}
 
-	// Creating a variable inside the if statement
-
 	if 9%2 == 0 {
 		fmt.Println("9 is even")
 	} else {

Go/Concepts/16) loops.go

@@ -11,7 +11,7 @@ func main() {
 	// }
 
 	sum := 0
-	for i := 0; i < 10; i++ {
+	for i := 0; i < 10; i++ { //for [initialization]; [condition]; [post] { }
 		sum += i
 	}
 	fmt.Println(sum)
@@ -22,16 +22,19 @@ func main() {
 		fmt.Println(days[i])
 	}
 
+	// for [index] := range [array] { }
 	for i := range days { // Better way to iterate over an array
 		fmt.Println(days[i])
 	}
 
+	// for [index], [value] := range [array] { }
 	for i, day := range days { // This is the preferred way to iterate over an array
 		fmt.Println(i, day) // i is the index and day is the value
 	}
 
+	// for _, [value] := range [array] { }
 	for _, day := range days { // we can ignore the index by using _
-		fmt.Println(day) 
+		fmt.Println(day)
 	}
 
 }

Go/Concepts/18) break-continue.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 )
 
+// continue: Will skip that ireration, but will not break the look unlike "break"
+
 func main() {
 	for i := 0; i < 5; i++ {
 		if i == 3 { // Here 3 will not be printed

Go/Concepts/19) function.go

@@ -19,7 +19,7 @@ func greetUser() {
 	fmt.Println("Hello, welcome to the app")
 }
 
-func addTwoNumbers(a int, b int) int { // Function with Para
+func addTwoNumbers(a int, b int) int { // Function with Para and retun value
 	return a + b
 }
 

Go/Concepts/20) methods.go

@@ -2,27 +2,26 @@ package main
 
 import "fmt"
 
-
-type UserData struct  { // struct is a collection of fields. 
-	fistName string
-	lastName string
-	email string
+type UserData struct { // struct is a collection of fields.
+	fistName        string
+	lastName        string
+	email           string
 	numberOfTickets int
 }
 
 func main() {
 	user := UserData{ // struct initialization
-		fistName: "John",
-		lastName: "Doe",
-		email: "[email protected]",
+		fistName:        "John",
+		lastName:        "Doe",
+		email:           "[email protected]",
 		numberOfTickets: 2,
 	}
 
 	fmt.Println(user)
 
-	user.greetUser() // Method call	
+	user.greetUser() // Method call
 }
 
 func (u UserData) greetUser() { // method with receiver
 	fmt.Println("Hello", u.fistName, u.lastName)
-}
+}

Go/Concepts/23) files.go

@@ -3,14 +3,17 @@ package main
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 )
 
 func main() {
-	content := "Hello, playground!"
 
-	file, err := os.Create("./test.txt")
+	// Process to create, write and read a file
+
+	content := "Hey I am Pradumna"
+
+	//"." means current directory
+	file, err := os.Create("./hello.txt")
 
 	if err != nil {
 		panic(err)
@@ -21,20 +24,16 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
-	fmt.Println("Length of the file is: ", length)
-	defer file.Close()
-
-	readFile("./test.txt")
 
-}
-
-func readFile(filename string){
+	fmt.Println("Length:", length)
 
-	databyte, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile("./hello.txt")
 
 	if err != nil {
 		panic(err)
+
 	}
 
-	fmt.Println("Text data inside a file is \n", string(databyte))
+	// data is of type []byte so we need to convert it to string
+	fmt.Println(string(data))
 }

Go/Concepts/24) handling-web-req.go

@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 )
 
@@ -16,7 +16,7 @@ func main() {
 	fmt.Printf("Response is of type: %T\n", res)
 	fmt.Println(res.Status)
 
-	databytes, err := ioutil.ReadAll(res.Body) //We can't read the response directly. So we use ioutil.ReadAll()
+	databytes, err := io.ReadAll(res.Body) //We can't read the response directly. So we use ioutil.ReadAll()
 	checkNilError(err)
 
 	content := string(databytes) // convert the byte array to string

Go/Concepts/25) handling-url.go

@@ -9,27 +9,26 @@ const myURL = "https://pradumnasaraf.dev:3000/services?service=twitter"
 
 func main() {
 
-	fmt.Println(myURL)
-
-	// Parsing
-
+	// Parsing the URL
 	results, _ := url.Parse(myURL)
-	fmt.Println(results.Scheme)
-	fmt.Println(results.Host)
-	fmt.Println(results.Port())
-	fmt.Println(results.RawQuery)
-	fmt.Println(results.Query())
+	fmt.Println(results.Scheme)   // Scheme is the protocol used. Eg: http, https, ftp, etc
+	fmt.Println(results.Host)     // Host is the domain name
+	fmt.Println(results.Port())   // Port is the port number
+	fmt.Println(results.RawQuery) // RawQuery is the query string
+	fmt.Println(results.Query())  // Query is the query string in map form
 
 	data := results.Query()
 	fmt.Println(data["service"])
 
+	// &url.URL{} is a pointer to a url.URL type
 	partsOfUrl := &url.URL{
-		Scheme: "https",
-		Host: "pradumnasaraf.dev",
-		Path: "/services",
+		Scheme:   "https",
+		Host:     "pradumnasaraf.dev",
+		Path:     "/services",
 		RawQuery: "user=pradumna",
 	}
 
+	// String() method is used to convert the url.URL type to string
 	anotherUrl := partsOfUrl.String()
 	fmt.Println(anotherUrl)
 }

Go/Concepts/26) basic-server.go

@@ -11,6 +11,6 @@ func main() {
 	http.ListenAndServe(":8080", nil)
 }
 
-func hello(w http.ResponseWriter, r *http.Request) {
+func hello(w http.ResponseWriter, r *http.Request) { // w is used to write the response and r is used to read the request
 	w.Write([]byte("Hello World"))
 }