为什么65.6 * 100％10等于9，而不是PHP中的0? [英] Why does 65.6*100%10 equals to 9, instead of 0 in PHP?

问题描述

echo 65.7 * 100 % 10 // 0

echo 65.6 * 100 % 10 // 9 <---

echo 6560 % 10       // 0

echo 65.5 * 100 % 10 // 0

有人可以解释为什么吗?

Can someone please explain why?

对于人类或非程序员，结果9显然是错误的.

for human or non-programmers, the result 9 is apprently wrong.

在编程时如何防止此"error"?

推荐答案

因为浮点中的65.6实际上是65.6的近似值.实际上实际上小于65.6，即65.5999或类似值.

Because 65.6 in floating point is actually an approximation of 65.6. It is actually marginally less than 65.6, i.e. 65.5999 or similar.

假设我对实际值的疯狂猜测是正确的，则您有6559.9，它是

Assuming my wild guess at the actual value is correct, you have 6559.9, which is stripped to 6599 by the modulus operator, then divided by 10 for remainder 9.

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