map
map中元素为结构体，不能直接修改，因为map元素无法取地址；
type Student struct {
name string
}
修改map中struct元素的值，错误示例：
func TestMap(t *testing.T) {
m := map[string]Student11{"people": {"zhoujielun"}}
//编译错误 Cannot assign to m["people"].name
m["people"].name = "wuyanzu"
}
解决办法：
func TestMap(t *testing.T) {
//Student => *Student
m := map[string]*Student{"people": {"zhoujielun"}}
//编译错误 Cannot assign to m["people"].name
m["people"].name = "wuyanzu"
}