for KC

gistfile1.go

package main

import "fmt"

func main() {
    v := []int{1,2,3,4,5,6,7,8}
    mv := new(MeanValue)
    /*mvFunc := mv.exec()*/
    nmv := new(MeanValue)
    nmvFunc := nmv.exec()
    for i := range v {
        nmvFunc(i)
    }
    fmt.Println(mv.value())
    fmt.Println(nmv.value())

}

type MeanValue struct {
    //go里面的各种类型都有个初始的零值，所以如你所愿，以下两个变量都会自动初始化为0
    m_value, m_num int
}

func (mv *MeanValue) exec() func(int) {
    return (func(ele int) {
        mv.m_value += ele
        mv.m_num++
    })
}

func (mv *MeanValue) value() float64 {
    fmt.Printf("m_value is %s, m_num is %s.\n", mv.m_value, mv.m_num)
    return float64(mv.m_value)/float64(mv.m_num)
}