为什么在MSVC中默认情况下浮点值（如3.14）被视为双精度值？ [英] Why floating point value such as 3.14 are considered as double by default in MSVC?

问题描述

为什么需要放置3.14f而不是3.14来禁用所有这些警告？
这是一个一致的原因吗？

解决方案

这是C ++（和C）浮点文字的类型为double，如果您需要它们为浮点型，则使用 f 后缀。似乎没有任何明确说明的原因，为什么，但我猜想它是a）与C兼容，和b）精度和存储之间的权衡。

2.13.3浮动文本浮动文本的类型
是double，除非后缀明确指定了
。
后缀f和F指定float，后缀l和L指定long double。
如果换算的值不在
范围内，那么它的类型的可表示的值，程序是不成形的。

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 ?

解决方案

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 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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