％运算符和IEEEremainder()方法之间Java的区别(如果有)? [英] Difference in Java, if any, between the % operator and the IEEEremainder() method?

问题描述

在Java中，使用％运算符获取整数除以x/y的余数与Math.IEEEremainder(x，y)方法之间在功能或性能上有什么区别吗?

In Java, is there any functional or performance difference between using the % operator to get the remainder of an integer division x / y, and the Math.IEEEremainder( x, y ) method?

推荐答案

除了John B指出的类型差异之外，语义上也存在显着差异. Math.IEEEremainder(x, y)返回x - n * y，其中n是x / y的最接近整数(在出现平局的情况下取偶数)，而x % y返回x - n * y，其中是x / y的整数部分(即n是将x / y的真实值四舍五入而不是四舍五入的结果).

Apart from the type difference already pointed out by John B, there's a significant difference in semantics, too. Math.IEEEremainder(x, y) returns x - n * y where n is the closest integer to x / y (taking the even integer in the case of a tie), while x % y returns x - n * y where n is the integer part of x / y (i.e., n is the result of rounding the true value of x / y towards zero, instead of towards nearest).

为了说明不同之处:Math.IEEEremainder(9.0, 5.0)将是-1.0，因为最接近9.0 / 5.0的整数是2，而9.0 - 2 * 5.0是-1.0.但是9.0 % 5.0将是4.0，因为9.0 / 5.0的整数部分是1，而9.0 - 1 * 5.0是4.0.

To illustrate the difference: Math.IEEEremainder(9.0, 5.0) would be -1.0, since the closest integer to 9.0 / 5.0 is 2, and 9.0 - 2 * 5.0 is -1.0. But 9.0 % 5.0 would be 4.0, since the integer part of 9.0 / 5.0 is 1 and 9.0 - 1 * 5.0 is 4.0.

这是 Math.IEEEremainder的官方文档.

Here's the official documentation for Math.IEEEremainder.

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