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。

麻省理工公开课 - 计算机科学及编程导论课程节选

Both effects hurt returns.

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The compounding effects of daily returns will actually throw off the math, and can do so in a very drastic way.

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To that point I would say it is precisely in this kind of long-term challenge, where there are demonstrable and potentially irreversible social effects, with returns accruing over periods beyond commercial discounting, that government must play a clear role.

ECONOMIST: Tony Blair