2022-10-31：以下go语言代码输出什么？A：map[]；B：nil；C：Panic；D：编译错误。
package main
import "fmt"
func main() {
var m map[string]int
delete(m, "oh noes!")
fmt.Println(m)
}
答案选A。在 delete 函数的文档有说明：The delete built-in function deletes the element with the specified key (m[key]) from the map. If m is nil or there is no such element, delete is a no-op.这意思是没有元素的时候，啥都不做。
