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javaoperatorsbit-manipulationcompound-operator

java bitwise operators and the equal character; compound operators

I'm a bit confused:

long v = 0;
v <<= 8; 
v |= 230;

I know << is the signed left shift operator and | Bitwise the inclusive OR but I'm confused to what the equals does?

So fist v is 0. So << doesn't have any effect? Then it equals 1000 but what happens then?

edit: I've edited the title so others might better find this question: added "compound operators"

Solution

  • There are somewhat like +=.

    For example x+=3 means add 3 to x; store to x.

    v <<= 8;

    left-shifts v 8 bits, and stores to v, functionally equivalent to v=v << 8.

    v |= 230;

    does a bitwise OR with 230 and stores back to v, equivalent to v=v | 230.

    Now, due to performance constraints and optimizations this operation may be done in place at a low level.