add helloworld program

Author: tbhaxor

helloworld/go.mod

@@ -0,0 +1,3 @@
+module helloworld
+
+go 1.20

helloworld/main.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+"fmt"
+"os"
+)
+
+// main is like any other programming language,
+// is the application's entry point.
+// Exactly 1 definition of this function is required in main package
+func main() {
+// check user has provided any
+// https://pkg.go.dev/os@go1.20.5#Args
+// https://pkg.go.dev/builtin#len
+if len(os.Args) > 1 {
+// take the second element of the array and print hello to user
+// https://pkg.go.dev/fmt@go1.20.5#Printf
+fmt.Printf("Hello, %s\n", os.Args[1])
+} else {
+// if no argument is provided, print message with new line
+// https://pkg.go.dev/fmt@go1.20.5#Println
+fmt.Println("Hello Guest")
+}
+}