c ++ float to bool转换 [英] c++ float to bool conversion

问题描述

我在看一些第三方代码，我不确定一行是做什么。我不能发布确切的代码，但它是沿着这样的线：

I'm looking at some 3rd party code and am unsure exactly what one line is doing. I can't post the exact code but it's along the lines of:

bool function(float x)
{
float f = doCalculation(x);
return x > 0 ? f : std::numeric_limits<float>::infinity();
}

这显然会引起编译器关于转换float-> bool的警告，实际行为是什么？ Visual C ++如何将浮动转换为bools？至少我应该能够替换那个讨厌的无限...

This obviously throws a warning from the compiler about converting float->bool, but what will the actual behaviour be? How does Visual C++ convert floats to bools? At the very least I should be able to replace that nasty infinity...

推荐答案

我认为这是一个错误。该函数应该返回一个浮点数。这对我来说似乎符合逻辑。

I think it is a mistake. That function should return a float. This seem logical to me.

浮动到bool的转换与float！= 0相同。但是，严格比较两个浮点并不总是如你所期望的，由于精度。

The conversion float to bool is the same as float != 0. However, strict comparing two floating points is not always as you'd expect, due to precision.

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