java - 如何在 Java 或 Groovy 中找到下一个 Double？

Question

当有一个 Double d 时，我想知道哪个 Double' 是比 d 大的最小可能值。

当 d==0 我知道答案时，那将是 Double.MIN_VALUE :

> 0d + Double.MIN_VALUE
4.9E-324

但是所有其他数字(例如 1d)呢？

> 1d + Double.MIN_VALUE
1.0

我想它必须与重要数字有关，但简而言之:我正在寻找一种方法来给我下一个双数

nextDouble(0)==4.9E-324

Answer 1

看看这些函数。

public static double nextAfter(double start, double direction)

Returns the floating-point number adjacent to the first argument in the direction of the second argument. If both arguments compare as equal the second argument is returned.

public static double nextUp(double d)

Returns the floating-point value adjacent to d in the direction of positive infinity. This method is semantically equivalent to nextAfter(d, Double.POSITIVE_INFINITY); however, a nextUp implementation may run faster than its equivalent nextAfter call.