Added a new tutorial in go-lang

tutorials/learn-golang.org/en/Comments Constants.md

@@ -0,0 +1,133 @@
+# Go Tutorial: Comments, Constants, and iota
+
+## Comments
+
+In Go, comments are notes left by a programmer in the source code that are completely ignored by the compiler.
+They are used to add explanations, make notes, or prevent code from running.
+
+Go has two types of comments:
+
+* **Single-line comments**: Start with `//`. Everything from the `//` to the end of the line is a comment.
+* **Multi-line comments**: Start with `/*` and end with `*/`. They can span multiple lines.
+
+### Examples
+
+**Single-line Comment:**
+
+
+    // This line prints a welcome message to the console. 
+    fmt.Println("Welcome to Go!")
+
+
+**Output:**
+
+```text
+    Welcome to Go!
+```
+
+**Multi-line Comment:**
+
+
+    /*
+    This is a multi-line comment.
+    It can be used to write longer explanations
+    or to comment out a block of code.
+    */
+    fmt.Println("Hello World!")
+
+
+**Output:**
+
+```text
+Hello World!
+```
+
+---
+
+## Constants (`const`)
+
+In Go, the `const` keyword declares constants—values that are fixed at compile time and cannot be changed later.
+They are perfect for defining configuration settings or mathematical constants.
+
+### Example
+
+
+    package main
+
+    import "fmt"
+
+    const (
+        AppName    = "My Awesome App"
+        Version    = "1.0.2"
+        MaxRetries = 3
+    )
+
+    func main() {
+        fmt.Println("Starting", AppName, "version", Version)
+        fmt.Println("Maximum retries:", MaxRetries)
+    }
+
+
+**Output:**
+
+```text
+Starting My Awesome App version 1.0.2
+Maximum retries: 3
+```
+
+---
+
+## iota
+
+`iota` is a special identifier used within a `const` block to create a sequence of related values.
+It acts as a counter that starts at `0` and increments by one for each subsequent constant declaration.
+This makes it incredibly useful for creating enumerations.
+
+### Example
+
+
+    package main
+
+    import "fmt"
+
+    const (
+        Sunday = iota // Sunday = 0
+        Monday        // Monday = 1 (implicitly iota)
+        Tuesday       // Tuesday = 2 (implicitly iota)
+    )
+
+    func main() {
+        fmt.Println("Sunday:", Sunday)
+        fmt.Println("Monday:", Monday)
+        fmt.Println("Tuesday:", Tuesday)
+    }
+
+
+**Output:**
+
+```text
+Sunday: 0
+Monday: 1
+Tuesday: 2
+```
+
+Exercise
+--------
+
+Create a Go program using `const` and `iota` to represent three **log levels**:  
+- `Info`  
+- `Warning`  
+- `Error`  
+
+Assign them values using `iota`, and then print them out.
+
+---
+
+### Expected Output Example
+
+    Info: 0
+    Warning: 1
+    Error: 2
+
+
+

tutorials/learn-golang.org/en/Welcome.md

@@ -18,6 +18,7 @@ learn-golang.org is still under construction - If you wish to contribute tutoria
 - [[Loops]]
 - [[Functions]]
 - [[The fmt module]]
+- [[Comments_Constants]]
 
 ### Contributing Tutorials