the-way-to-go_ZH_CN/eBook/exercises/chapter_5/i_undefined.go

// i_undefined.go
package main

import (
	"fmt"
)

func main() {
	var i int
	for i = 0; i < 10; i++ {
		fmt.Printf("%v\n", i)
	}
	fmt.Printf("%v\n", i) //<-- compile error:  undefined i
}