fun main() { val str: String? = null val length = str?.length ?: -1 println(length) }
编译错误
运行错误,抛出 NullPointerExcepiton
0
-1
这道题你会答吗?花几分钟告诉大家答案吧!
扫描二维码,关注牛客网
下载牛客APP,随时随地刷题