PHP 用负数计算给出了错误的值 [英] PHP calculating with negative numbers gives wrong values

问题描述

我的 PHP 代码:

echo -100.35+100.00;
echo '<br/>';
echo -478.35+478.32+0.03;

给出输出:

-0.34999999999999
-2.9559688030645E-14

我不明白为什么，我尝试在值前面(浮动)但没有区别.

I don't understand why, i tried (float) in front of the values but no difference.

推荐答案

看看 本手册，它解释了浮点数的内部表示并非 100% 准确……这与我怀疑的浮点数的内部表示有关.

Take a look at this manual, it explains that the internal representation is not 100% exact for floats... it has to do with the internal representation of the floats I suspect.

手册中也提到了这些方法和这些用于需要精度的计算.

The manual does also refer to these methods and also these for calculations with need of precision.

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