Advertisements I want to declare the constructor outside of the class but there is something wrong with the template code. template <size_t size = 1> class my_class { public: template <class int_t> constexpr my_class(int_t); }; template<class int_t, size_t size> constexpr my_class<size>::my_class(int_t num) { } but this works: template <size_t size = 1> class my_class {… Read More template code declared outside of class doesn't compile
Advertisements I have a template class that forwards a function: template <class T> class Foo{ template <typename Func, typename… Args> void Bar(Func function, Args&&… args) { T t; (t->*function)(std::forward<Args>(args)…); } } This works, but is there any way to check whether Func is contained in the interface of T, so T::Func? Now, if I enter… Read More Specify function interface in template
Advertisements The following construct is a minimal example of what I try to achieve: let the return type of a templated function depend on the input types. First I wrote (below a selection of a set that also specializes for std::complex<> variants): template<class U, class V> struct result_type { using type = U; }; template<>… Read More How to determine function output type based on template parameters?
Advertisements In the following example: template<typename T> struct MyList { typedef std::list<T> type1; }; template<typename T> class MyList2 { typename MyList<T>::type1 type2; }; I thought that both type1 and type2 are dependent name since both of their types depend on the template parameter. However, why is the first one considered non-dependent since I can use… Read More Dependent names vs non-dependent names
Advertisements In my main function, I have a bunch of priority_queues all of them have int in them, but some have less<int>, others have greater<int>: //std:: removed for clarity priority_queue<int, vector<int>, less<int>> pq1; priority_queue<int, vector<int>, greater<int>> pq2; I wish to make a function that accepts two priority_queue by reference and pops the first and puts… Read More How do I pass a 'general' priority_queue as function argument in c++
Advertisements I looked up to this and this SO answers, but none solves my problem. Short description: the template function, where much more should happen than just that of this example, should be able to wrap any other function, also function members of a class. Minimal working example: #include <iostream> template <typename T, typename …ArgsT>… Read More Correct template definition to wrap class member functions
Advertisements I have a class template that has a parameter pack and that class template has a member function template which also have a parameter pack. Now inside that member function template, I need to know whether the two template parameter packs are same(meaning they have same length as well as all of their corresponding… Read More Checking if two template parameter packs are same
Advertisements Let’s assume we want to print out the attribute of an arbitrary class through two different functions: One function takes a parameter const Widget&, the other one is a function template that takes a parameter of type const T&. We pass one argument of type Widget and Widget& respectively. The code can look like… Read More Syntactic restriction in function vs. function template when passing an address
Advertisements header.h: #include <iostream> template<typename T> class Test { public: __attribute__((noinline)) void fun(int a, int b) { std::cout << a + b << std::endl; } }; class SpecialClass {}; a.cpp: #include "header.h" int main() { Test<SpecialClass> test; test.fun(10, 8); return 0; } b.cpp: #include "header.h" template<> void Test<SpecialClass>::fun(int a, int b) { std::cout << a… Read More Is template specilization in different source file undefined behavior?
Advertisements This code compiles with GCC, but gives ambiguous call to overloaded function for MSVC: https://godbolt.org/z/W89xn15d3 #include <string> template <typename Iter> void reverse(Iter begin, Iter end){ if (std::distance(begin, end) == 0) return; auto left = begin, right = std::prev(end); while (left < right) std::swap(*left++, *right–); } std::string reverseWordsInString(std::string str) { reverse(str.begin(), str.end()); // ambiguous call… Read More ambiguous call to function template (reverse)