You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: main.go
    path of file: ./repos/build-web-application-with-golang/de/code/src/apps/ch.2.3/pass_by_value_and_pointer
    
    the code of the file until where you have to start completion: // Example code for Chapter 2.3 from "Build Web Application with
    
func show_add_by_reference() {
	x := 3
	fmt.Println("x = ", x) 
	// &x pass memory address of x
	fmt.Println("add_by_reference(&x) =", add_by_reference(&x) )
	fmt.Println("x = ", x) 
}