I just came across the following line inside some sourcecode.
int sequ |= element.sequence
What does the operator |= mean ? I haven't seen that before.
Asked
Active
Viewed 1,620 times
0
-
1means int sequ = sequ | element.sequence – Matthias Sep 04 '13 at 11:12
-
1Use http://www.symbolhound.com/ for searching something like that, see the [results](http://www.symbolhound.com/?q=%7C%3D+java) – Habib Sep 04 '13 at 11:12
-
A list of operators can be found here http://www.tutorialspoint.com/java/java_basic_operators.htm – Qben Sep 04 '13 at 11:14
2 Answers
4
=| is a compound assignment operator, similar to +=, -=, /=, or *=, but with bitwise OR instead.
This is equivalent to:
sequ = (int) (sequ | element.sequence);
where | is the bitwise OR operation, meaning that it independently ORs all bits in the left operand with those in the right operand, to get a result. The cast is not necessary if element.sequence is already an int.
Note: Your original code wouldn't make sense:
int sequ |= element.sequence
You can't declare it there and then and or it with something else. It would need to have been declared and assigned before, such as in:
int sequ = 0; /* or some other value */
sequ |= element.sequence;
nanofarad
- 40,330
- 4
- 86
- 117
-
@WalterM According to the [Java language spec](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.26.2), `E1 op= E2` *is* `(T) ((E1) op (E2))`, which is pretty much the same thing as what I stated, possibly with a cast to the LHS type. If you were in fact talking about casting to int if element.sequence wasn't int, it would have been nice to leave a less cryptic comment. Also, to answer, "If they really were equivalent, then why would we need both?", why would we need `+=` then, if we can just assign the sum manually? – nanofarad Dec 31 '15 at 16:34
2
It is short form for:
int sequ = sequ | element.sequence;
Similar to +=, -= except that it is bitwise OR operator.
Azodious
- 13,752
- 1
- 36
- 71