CODEWITHSUNDEEP
c++typescasting
Tero de la Rosa
Tero de la Rosa

Reputation: 31

How to make a similar cast like 1LL with any other type?

Does this make any sense?

    static_cast<long long>(1) == 1LL
    static_cast<float>(1) =? 1F

Is there a short way of making the casting for other types such as float? Thank you very much!

Upvotes: 3

Views: 165

Answers (2)

Mike Seymour
Mike Seymour

Reputation: 254501

This answer describes C++11. User-defined literals, and some of the types, didn't exist in historic versions of the language.

Integer literals can end with nothing, L, LL, U, UL or ULL giving a type of int, long, long long, unsigned int, unsigned long or unsigned long long respectively. These can be in lower case if you like; and the actual type may be wider than specified if necessary to represent the value.

Floating-point literals can end with nothing, F or L giving a type of double, float or long double respectively. Again, these can be in lower case if you like.

Character and string literals can begin with nothing, u, U or L, giving a character type of char, char16_t, char32_t or wchar_t respectively. Strings can also begin with u8 to indicate a char character type with UTF-8 encoding.

You can also define your own user-defined literals to make literals of any type, if you find weird things like 123_km more readable than kilometres(123). I don't see the point of that, but someone's posted an example if you're interested.

Upvotes: 6

awesoon
awesoon

Reputation: 33671

Since C++11 you could define your own literals. For example, you could define literal _F like this:

float operator"" _F(unsigned long long l)
{
    return static_cast<float>(l);
}

int main()
{
    auto a = 1_F;
    static_assert(std::is_same<decltype(a), float>::value, "Not a float");
    return 0;
}

Upvotes: 8

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