access-counter.go

package main

import (
	"net/http"
	"strconv"
)

var counter int

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		counter++
		w.Write([]byte("あなたは" + strconv.Itoa(counter) + "人目の訪問者です"))
	})
	http.ListenAndServe(":8080", nil)
}