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c++returnreturn-valueoperator-precedence
user2672807
user2672807

Reputation: 1

C++ Operator precedence and the return statement

If I do something like return a ? b : c; or return a && a2 && a3;

Could it ever be evaluated as just return a and then the function just returns immediately before evaluating the rest?

Upvotes: 7

Views: 2804

Answers (3)

Mark Ransom
Mark Ransom

Reputation: 308121

To make this clearer I'm going to restate the question a little:

return a ? b() : c();

return a && a2() && a3();

In the first case, one of either b or c will be called but not the other.

In the second case, if a is false then neither a2 nor a3 will be called. If a2 returns false, a3 won't be called.

Upvotes: 2

Kerrek SB
Kerrek SB

Reputation: 476970

return is a statement, not an expression. So it can never be misinterpreted the way you think.

The statement is always of the form return [some expression]; (and the expression is optional). The expression, if present, is evaluated first, and its value is bound to the return value of the function.

Upvotes: 8

Fred Larson
Fred Larson

Reputation: 62063

In return a && a2 && a3;, if a is false, there's no need to evaluate the rest of the expression. The result will always be false. So a2 and a3 will not be evaluated. This is called "short circuiting".

Upvotes: 1

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