Logical operator OR without short circuit [duplicate]

Question

When would you ever need to use the non short circuit logical operator or? In other words...

When would you use

if(x == 1 | x==2)

Instead of

if(x == 1 || x==2)

If the first conditional is true... Then the entire statement is already true.

Update: and the same question for & and &&

Answer 1

One example arises if we have two functions and we want them both to be executed:

if (foo() | bar())

If we had used ||, then bar() will not be executed if foo() returns true, which may not be what we want.

(Although this is somewhat of an obscure case, and more often than not || is the more appropriate choice.)

An analogous situation can come up with &/&&:

if (foo() & bar())

If we had used &&, then bar() will not be executed if foo() returns false, which again may not be what we want.

Answer 2

Well, there are a few reasons. Take the following example:

if(someImportantMethod() | otherImportantMethod())
{
    doSomething();
}

If you needed both methods to be run, regardless of the result of the other method, then you'd have to use | instead of ||.

Something to note is that the short circuit operands are slightly slower (though the performance impact is usually unnoticable).