为什么整数除法代码给出错误答案? [英] Why does integer division code give the wrong answer?

问题描述

我在 Java 中有一个非常简单的划分(它是每小时的产品数量/产量)，但是每当我进行这个划分时，我都会遇到奇怪的错误:

I have a very simple division in Java (it's a product quantity / production per hour), however whenever I make this division I get strange errors:

float res = quantity / standard;

我已经用多个值尝试了上述除法，但总是出错，但是我在其他任何地方都尝试过并且正确的是:

I have tried the above division with several values and I always get errors, however the one that I've tried everywhere else and gotten right was this:

世界各地:

13.6 = 6800 / 500;

Java:

13.0 = 6800 / 500;

我研究了 BigDecimal 和 BigInteger，但是我还没有找到用它们创建这个除法的方法，有没有其他方法可以在没有精度错误的情况下在 Java 中进行这个除法??

I've researched BigDecimal and BigInteger, however I haven't found a way to create this division with them, is there any other way to do this division in Java without having precision errors??

任何帮助将不胜感激.

推荐答案

你在对整数进行除法，这意味着你在使用整数除法.

You're dividing integers, which means that you're using integer division.

在整数除法中，结果的小数部分被丢弃.

In integer division the fractional part of the result is thrown away.

尝试以下操作:

float res = (float) quantity / standard;
            ^^^^^^^

以上强制将分子视为 float ，这反过来又促进分母浮动，并且执行 float-division 而不是 int-division.

The above forces the numerator to be treated as a float which in turn promotes the denominator to float as well, and a float-division is performed instead of an int-division.

请注意，如果您正在处理文字，则可以更改

Note that if you're dealing with literals, you can change

float f = 6800 / 500;

包含 f 后缀以使分母为浮点数:

to include the f suffix to make the denominator a float:

float f = 6800f / 500;
              ^

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