Go每日一题_073

func f1() (r int) {
    defer func() {
        r++
    }()
    return 0
}


func f2() (r int) {
    t := 5
    defer func() {
        t = t + 5
    }()
    return t
}


func f3() (r int) {
    defer func(r int) {
        r = r + 5
    }(r)
    return 1
}