groovy - Groovy 中奇怪的除法运算符

Question

我是 Groovy 新手。

为什么这会在运行时抛出异常:

int[] a = [1,2,3,4,5]
int lo=0
int hi=4

int x = a[(lo+hi)/2]
assert x == 3

虽然这些都可以:

int x = a[(int)(lo+hi)/2]

和

int i = (lo+hi)/2
int x = a[i]

Answer 1

在 groovy 中，如果操作数的类型为 Integer、Long、BigInteger，则除法结果为 BigDecimal或BigDecimal:

例如参见 this tutorial :

The division operators "/" and "/=" produce a Double result if either operand is either Float or Double and a BigDecimal result otherwise (both operands are any combination of Integer, Long, BigInteger, or BigDecimal).

[...]

For example

1/2 == new java.math.BigDecimal("0.5");

[...]

Integer division can be performed on the integral types by casting the result of the division. For example:

assert (int)(3/2) == 1I;