I'm much better having an exception get handled at the time of input than to let that prop -- that value rather propagate through a whole bunch of code until eventually it hits an error 17 calls later, and you have no clue where it came from.

不是我期望的格式,这时我最好有一个异常处理,而不是让其传下去,这个值传到代码的整个分支,最终会导致一个错误17调用的发生，并且你不知道这个错误是哪里来的。

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X I'm passing an X, and yet I'm also assigning the return value to X. So just intuitively what's going to be the effect of this one line of code?

我传一个X，之后我把返回值赋值给,很明显，这一行代码,将会产生什么作用？

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