what does the `?` operator mean in C++?

Question

I was just reading some articles on Wikipedia involving some code in C++, but I was unfamiliar with one of the operators used, ?. Here's the context in which it was used:

unsigned int factorial(unsigned int n) {
    return n == 0 ? 1 : n * factorial(n - 1); 
}

Same as IF statement. It means .. if(n==0) return 1; else return (n * factorial(n - 1)); — Sung, Jul 31 '15 at 00:01
Excuse me, but there's no need to downvote this question. I did look to see if it had already been answered, but the problem was I was using the word operator, so the answer was excluded. — lorentzfactor, Jul 31 '15 at 01:56
For what little it's worth, even googling "c++ question mark" gets useful results right away (including that other stackoverlfow question as the first result). — TheUndeadFish, Jul 31 '15 at 02:25

score 1 · Answer 1 · answered Jul 31 '15 at 00:01

1

condition ? true-outcome : false-outcome

Same as:

if (n == 0) {
    return 1;
} else {
    return n * factorial(n - 1);
}

answered Jul 31 '15 at 00:01

Dan Lowe

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Not exactly the same, you can't use if statements as an expression. – ChaosPandion Jul 31 '15 at 00:02
In particular, tenaries can be used to initialize a const variable. – Caninonos Jul 31 '15 at 00:05

what does the `?` operator mean in C++?

1 Answers1