So, playing around with constexpr, MSVC (Visual Studio 2012) gave me an error while trying to qualify my function with the constexpr keyword using this simple program (includes omitted):
constexpr int factorial(int n) { return n <= 1 ? 1 : (n * factorial(n-1)); } int main(void) { const int fact_three = factorial(3); std::cout << fact_three << std::endl; return 0; } constexpr was underlined red with the following message:
Error : this declaration has no storage class or type specifier
and trying to compile the program gave the following output:
1>main.cpp(5): error C2144: syntax error : 'int' should be preceded by ';'
1>main.cpp(5): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
It really puzzles me as it is the very example that Cppreference uses to illustrate the use of constexpr. At first I used a simple function that returned a literal, i.e. constexpr int func(){return 5;}, but which yielded the same error. I interpreted the first message as "it should be a member function of a struct or class", but the example from Cppreference shows that it's not necessary apparently.
So, what am I obviously missing here ?
