为什么在 MSVC 中默认情况下将浮点值(例如 3.14)视为双精度值?

Why floating point value such as 3.14 are considered as double by default in MSVC?(为什么在 MSVC 中默认情况下将浮点值(例如 3.14)视为双精度值?)

问题描述

为什么我需要使用 3.14f 而不是 3.14 来禁用所有这些警告?这有什么连贯的原因吗?

Why do I need to put 3.14f instead of 3.14 to disable all those warnings ? Is there a coherent reason reason for this ?

推荐答案

这是 C++(和 C)标准决定的.浮点文字是 double 类型的，如果您需要它们是浮点数，您可以使用 f 后缀.似乎没有任何具体说明原因，但我猜是 a) 与 C 兼容，b) 精度和存储之间的权衡.

That's what the C++ (and C) standard decided. Floating point literals are of type double, and if you need them to be floats, you suffix them with a f. There doesn't appear to be any specifically stated reason as to why, but I'd guess it's a) For compatibility with C, and b) A trade-off between precision and storage.

2.13.3 浮动字面量 类型浮动文字的两倍，除非由后缀明确指定.这后缀 f 和 F 指定 float，后缀 l 和 L 指定 long double.如果缩放值不在范围其类型的可表示值，程序格式错误.

2.13.3 Floating literals The type of a floating literal is double unless explicitly specified by a suffix. The suffixes f and F specify float, the suffixes l and L specify long double. If the scaled value is not in the range of representable values for its type, the program is ill-formed.

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