If you're writing a one line function, whose sole purpose in life is addition, and, clearly, this is about addition, well, then it's, in fact, A reasonable to use a shorter symbol like A, but I do have to specify it's type.

如果你在写一个一行的函数，它唯一的目的是,做加法，显然这是关于加法的，好的，实际上，用一个短的标识符是合理的，像，但是我必须指明它的类型。

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And again, a related problem that people run into is side-effects. You call a function and it returns a value, but maybe it, on purpose or on accident, modifies one of the actual parameters.

另外，一个人们常碰到的相关问题,就是副作用，你调用一个函数它返回一个值,但是故意或者无意的,它可能会修改一个实参的值。

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