当值改变时终止

[计] break when value changes

dāng zhí gǎi biàn shí zhōng zhǐ ㄉㄤ ㄓˊ ㄍㄞˇ ㄅㄧㄢˋ ㄕˊ ㄓㄨㄥ ㄓˇ