使用sort包相关方法实现排序和逆序

只要结构体（集合）实现了Less、Swap、Len三个方法即可使用sort包相关方法实现排序等操作。
代码如下：

import (
    "fmt"
    "sort"
)

type student struct{
    name string
    age int
}
type stuSlice []student

func (s stuSlice)Len()int{
    return len(s)
}
func (s stuSlice)Less(i,j int)bool{
    return s[i].age<s[j].age
}
func (s stuSlice)Swap(i,j int){
    s[i],s[j] = s[j],s[i]
}


func main(){
    s:=stuSlice{}
    s = append(s,student{name:"xiaohong",age:29})
    s = append(s,student{name:"zhangsan3",age:18})
    s = append(s,student{name:"zhangsan",age:14})
    s = append(s,student{name:"zhangsan2",age:17})
    sort.Sort(s)
    fmt.Println("排序后结果：",s)
    sort.Sort(sort.Reverse(s))
    fmt.Println("逆序后结果：",s)
}