In the following code, is product guaranteed to contain a correct answer:
int num=INT_MAX, num2=INT_MAX;
long long product = num1 * num2;
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Natan Yellin
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5No, you must cast one of the multipliers. `long long product = (long long)num1 * num2;` – Weather Vane Nov 20 '17 at 08:54
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3There are only `int` values involved in the multiplication. Why should there be any type promotion? The assignement of the result only happens after the calculation is done. – Gerhardh Nov 20 '17 at 08:55
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the rule is that ~everything is promoted to int; or an integer type of greater rank if not all values of both operand types can be represented in a int... – Antti Haapala -- Слава Україні Nov 20 '17 at 09:00
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You will want to look at [C11 Standard - 6.3.1.1 Boolean, characters, and integers](https://port70.net/~nsz/c/c11/n1570.html#6.3.1.1) and see *Note 58*. – David C. Rankin Nov 20 '17 at 09:05
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@Gerhardh the problem is that multiplying 2 n-bit numbers produce a 2n-bit number, so what the OP asked is valid – phuclv Nov 20 '17 at 09:17
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@LưuVĩnhPhúc yes, but an overflow alone is no trigger for some type propagation. – Gerhardh Nov 20 '17 at 09:20