Member function call in decltype

Question

The following code:

struct A
{
    int f(int);
    auto g(int x) -> decltype(f(x));
};

Fails to compile with the error:

erro         


        

Answer 1

result_of and decltype in combination can give the the return type for a member function

#include 
using namespace std;

struct A
{
    int f(int i) { return i; } 
    auto g(int x) -> std::result_of::type
    { 
        return x;
    }
};


int main() {
    A a;
static_assert(std::is_same::value, 
                  "should be identical");
return 0;
}