PHP计算浮点数 [英] php calculate float

问题描述

我在这里有一个奇怪的数学计算.我希望有人能解释.

I have a weird math calculation here. I hope someone will explain.

$a = 1.85/100;
$b = 1.5/100;
$c = 1.1/100;
$d = 0.4/100;
$e = 0.4/100;
$f = 0.4/100;
$g = 0.4/100;

$h = $a + $b + $c + $d + $e + $f + $g;

echo $h*100 ."<br>";
$i = $h-$a;
$i = $i-$b;
$i = $i-$c;
$i = $i-$d;
$i = $i-$e;
$i = $i-$f;
$i = $i-$g;

echo $i;

最后一个$i值应为0，但返回6.93889390391E-18.

The last $i value should be 0 but it returns 6.93889390391E-18.

推荐答案

有什么办法纠正我的方程式以显示最终结果0.00吗?

any idea to correct my equation to show final result 0.00 ?

是的，round($i, 2)

差异"通常很小，以至于将其四舍五入到小数点后两位几乎总是可以解决问题.

The "discrepancies" are usually so small, that rounding it to 2 decimals will almost always solve the problem.

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