package main

import (
	"fmt"
	"strings"
)

func contact_str() {
	first_name := "Wei"
	last_name := "Guan"
	full_name := fmt.Sprintf("%s %s", first_name, last_name)
	fmt.Println(full_name)
}

func builder_str() {
	var str strings.Builder
	str.WriteString("Wei ")
	str.WriteString("Guan")
	fmt.Println(str.String())
}

func main() {
	contact_str()
	builder_str()
}