如何在J中编写此C表达式？

Question

如何在J中编写此C表达式？(x输入整数在哪里,a是临时变量)

((a= ~x & (~x >> 1)) ^= a ? 0 : (a ^ (a & (a - 1))) | (a ^ (a & (a - 1))) << 1);

.

编辑:

以更易读的形式:

    int a = (~x) & ((~x) >> 1);
    if (a == 0) return 0;
    int b = a ^ (a & (a - 1));
    return b | (b << 1);

Answer 1

没有测试,基本的转录将是这样的:

Shift =: (33 b.)
And   =: (17 b.)
Not   =: (26 b.)
Xor   =: (22 b.)
Or    =: (23 b.)

BastardFunction =: 3 : 0
  a =. (Not y) And (_1 Shift (Not y))
  if. a do.
    b =. a  Xor (a And a - 1)
    (1 Shift b) Or b
  else.
    0
  end.
)

但是可能有一个更聪明的方法.