The ||
operator is like |
(§15.21.2), but evaluates its right-hand operand only if
the value of its left-hand operand is false
. It is syntactically left-associative (it
groups left-to-right). It is fully associative with respect to both side effects and
result value; that is, for any expressions a, b, and c, evaluation of the expression
((
a)||(
b))||(
c)
produces the same result, with the same side effects occurring in the same order, as evaluation of the expression (
a)||((
b)||(
c))
.
ConditionalOrExpression:
ConditionalAndExpression
ConditionalOrExpression||
ConditionalAndExpression
Each operand of ||
must be of type boolean,
or a compile-time error occurs. The type of a conditional-or expression is always boolean
.
At run time, the left-hand operand expression is evaluated first; if its value is true
, the value of the conditional-or expression is true
and the right-hand operand expression is not evaluated. If the value of the left-hand operand is false
, then the right-hand expression is evaluated and its value becomes the value of the conditional-or expression. Thus, ||
computes the same result as |
on boolean
operands. It differs only in that the right-hand operand expression is evaluated conditionally rather than always.