我应该使用double还是float？ [英] Should I use double or float?

问题描述

在C ++中使用一个而不是另一个的优点和缺点是什么？

What are the advantages and disadvantages of using one instead of the other in C++?

推荐答案

如果你想知道真正的答案，您应该阅读每一个计算机科学家应该知道的浮点算术。

If you want to know the true answer, you should read What Every Computer Scientist Should Know About Floating-Point Arithmetic.

简而言之，虽然 double 允许表示，对于某些计算，它会产生较大误差。 正确选择是：使用尽可能多的精度，但不要更多和选择正确的算法。

In short, although double allows for higher precision in its representation, for certain calculations it would produce larger errors. The "right" choice is: use as much precision as you need but not more and choose the right algorithm.

许多编译器以非严格模式进行扩展浮点数学运算（即使用硬件中可用的更宽的浮点类型，例如80位和128位浮点数），这也应该考虑在内。实际上，您可以几乎看不到任何速度差异 - 它们本来就是硬件本身。

Many compilers do extended floating point math in "non-strict" mode anyway (i.e. use a wider floating point type available in hardware, e.g. 80-bits and 128-bits floating), this should be taken into account as well. In practice, you can hardly see any difference in speed -- they are natives to hardware anyway.

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