Non-terminating decimal expansion; no exact representable decimal result 两个double 类型相除 java 中文
时间: 2024-06-22 08:01:28 浏览: 7
当两个 `double` 类型的数值在 Java 中相除,结果可能是一个非终止的小数(Non-terminating decimal expansion),特别是在涉及到浮点数计算时。`double` 类型使用的是 IEEE 754 标准,它的精度有限,无法精确表示所有实数,尤其是某些有无限循环小数或无理数。例如,1/3 在十进制中就是无限循环的小数 0.3333...,而在 `double` 中只能近似表示。
当这样的除法运算产生一个无法精确表示的结果时,Java 会返回一个近似值,这可能会导致精度损失。如果结果是一个无限循环的小数,那么实际上是没有精确可代表的 decimal 结果的,因为 `double` 有其固定位数的存储限制。
相关问题
Non-terminating decimal expansion; no exact representable decimal result 两个double 类型相除 java
Non-terminating decimal expansion refers to a situation where the decimal representation of a mathematical fraction, when expressed as a floating-point number, does not have an exact representation in binary format used by computers. This occurs when the division of two numbers results in a non-terminating or recurring decimal pattern that cannot be represented precisely with the finite precision of a double data type, which has a limited number of bits for storing fractional parts.
In Java, specifically with the `double` type, this happens because the IEEE 754 standard used for floating-point arithmetic reserves some bits for the exponent and mantissa, leading to a finite set of possible values. When dividing two `double` numbers with an exact ratio that cannot be expressed as a simple fraction with integer coefficients, the result will be approximated based on these limitations.
For example, consider the division of 1 by 3 in decimal form, which is an infinite repeating decimal (0.3333...). If you try to store this value in a `double`, you will get an approximation like 0.3333333333333333, and if you perform calculations involving this number repeatedly, the sequence may start to diverge slightly due to rounding errors.
When such a case arises, it's important to handle the potential for inaccuracies in your code. You can use libraries like BigDecimal for more precise decimal arithmetic or implement custom algorithms to manage the precision issues.
Non-terminating decimal expansion; no exact representable decimal result的处理
当使用BigDecimal进行精确计算时,如果出现Non-terminating decimal expansion; no exact representable decimal result异常,可以通过指定舍入模式来解决。舍入模式可以在调用divide方法时作为参数传递。常见的舍入模式有:
1.ROUND_UP:向远离零的方向舍入。
2.ROUND_DOWN:向接近零的方向舍入。
3.ROUND_CEILING:向正无穷方向舍入。
4.ROUND_FLOOR:向负无穷方向舍入。
5.ROUND_HALF_UP:四舍五入,如果舍弃部分>= 0.5,则向远离零的方向舍入。
6.ROUND_HALF_DOWN:四舍五入,如果舍弃部分> 0.5,则向远离零的方向舍入。
7.ROUND_HALF_EVEN:如果舍弃部分左边的数字为偶数,则向远离零的方向舍入;否则,向接近零的方向舍入。
8.ROUND_UNNECESSARY:如果存在非精确结果,则抛出ArithmeticException。
例如,我们可以使用ROUND_HALF_UP舍入模式来解决Non-terminating decimal expansion; no exact representable decimal result异常:
```java
BigDecimal a = new BigDecimal("1");
BigDecimal b = new BigDecimal("3");
BigDecimal c = a.divide(b, 10, RoundingMode.HALF_UP);
System.out.println(c);
```
上述代码将1除以3,并将结果舍入到小数点后10位,使用ROUND_HALF_UP舍入模式。这样就可以避免Non-terminating decimal expansion; no exact representable decimal result异常的出现。
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