Shifting Operators?

[ietprofessional]

I'm trying to get Java certified and I'd like someone to explain to me why a programmer would use shifting operators?

<<, >>, >>>

I'm learning how they work but don't know why I would use them in the real world, unless it was for encrypting a number or something.

Thanks,

Harold

 

[sedj]

In Java, they are used when you need to manipulate bytes on a low level. As you suggested, cryptography is one use.

I've been programming Java for 3 years and have only ever used them once, when maipulating byte values on a TCP/IP stream.

Generally you won't use them - but its good to know how they work, as you can understand more about computing from them.



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[Diancecht]

Well, not in Java, as you won't do much bit processing on a such high level language.

But in other terms, they have real applications: number generation, Turing machines, streaming simulation, etc.

Cheers.

Dian

 

[Bong]

I occasionally use shifting when reading a nonstandard size value from a stream of telemetry. For example, I receive a 32bit word. The first 15 bits are a day counter; the last 17 bits are a seconds of day value (86400 seconds in 24 hours; 2^16=65536; 2^17=131072). I shift left by 15, then left by 15 and read the integer as a 32 bit word with leading zeros. I shift right by 17 and read the (day) integer as a 32 bit word.

Bob Rashkin
rrashkin@csc.com