Left shift operation in Crystal?

Help & Support
1

Hello,

I would like to do left shift operation on numbers, such as 1 << 32 which should give me 2^32.
Do you know how to do it in Crystal?

2

why not just 2**32

3

I’m pretty sure this is already a thing. https://crystal-lang.org/api/Int.html#<<(count%3AInt)-instance-method.

EDIT: https://play.crystal-lang.org/#/r/6xmn Note that im telling it the numbers are Int64, otherwise it would overflow and the output would be 0. Or, in future versions would raise an exception.

4

Thank you for you answer, indeed I was getting 0 because of the overflow.
Looking for ‘bit’ or ‘<<’ in the doc was not leading me toward the leftshift so i was thinking it was not the way to do it. Thank you for pointing me to the right documentation!

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5

Could you also explain me why
pp 56&-1
is giving 55? I mean -1 in the 2-complement representation is 0xFFFF… , but pp 56&0xFFFF is giving me the correct result (56).

6

You’re hitting the new “skip overflow check” operator &-, so your code is equivalent to pp 55.&-(1) not pp 55.&(-1).

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