templates

[Solved] std::vector inserting std::pair

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The original poster failed to actually post the code that was causing the problem. He has since edited my post with the correct code that demonstrates the problem. The code that demonstrates the problem follows: template <class R, typename B=int> class AVectorContainer { public: AVectorContainer() {} typedef R* ptr_Type; typedef const B & const_ref_Type; typedef … Read more

[Solved] istringstream to int8_t produce unexpected result

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The problem is int8_t is implemented as char. The implementation of the input stream is working like this: char x; std::string inputString = “abc”; std::istringstream is(inputString); is >> x; std::cout << x; The result is ‘a’, because for char the input stream is read char for char. To solve the problem, provide a specialised implementation … Read more

[Solved] C++ return a list of values? [closed]

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In your code, you declare to return type T, but the variable you return has type list<T>. I’d suggest to develop your code with concrete types (and without templates) first; you can exchange the concrete type with placeholders afterwards, but concrete types give a better idea what actually happens. Try the following code and translate … Read more

[Solved] c++ use template class [closed]

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Is there any way to compile this code such as inheritance, overload…? No. Not as you are trying to at least. mylist *y = new mylist(); //….how? isn’t valid since you have to provide a template parameter for mylist like mylist<MyType>. You’re probably looking for template specializations. 6 solved c++ use template class [closed]

[Solved] Two time template declaration

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The template arguments are placeholders, their scope is limited to that one declaration alone. Therefore, the T in template<class T> struct Alloc { }; is not connected to the T in template<class T> using Vec = vector<T, Alloc<T>>; similarly as you could use the same parameter name in different function declarations. 3 solved Two time … Read more

[Solved] Design table that it’s have long name with sorting sign and textbox for search

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I have looked up and down, tried all the different and various ways of being able to solve this problem,Then I find the Solution. You can use the text-overflow Property in CSS to not write long titles in multiple lines. Use this Style : th.fit { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; } Check out … Read more

[Solved] Is it considered “correct” to use a template for a function/class that only accepts subclasses of a specific class?

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It’s quite common, actually almost all templates have certain requirements towards their arguments. Those are usually implicitly clear from how the template parameter is used, but you can improve the error messages by using type traits. In C++11, they are available from the standard library via #include <type_traits>, otherwise look into Boost.TypeTraits. With C++11, the … Read more

[Solved] Transform std::pair to std::tuple with any number of elements

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Option #1 #include <cstddef> #include <type_traits> #include <utility> #include <tuple> template <typename A, typename B> struct merge_tuples { static_assert(std::tuple_size<A>::value == std::tuple_size<B>::value, “!”); template <std::size_t… Is> static auto merge(std::index_sequence<Is…>) noexcept -> std::tuple<typename std::decay<decltype(std::declval<typename std::tuple_element<Is, A>::type>() + std::declval<typename std::tuple_element<Is, B>::type>()) >::type…>; using type = decltype(merge(std::make_index_sequence<std::tuple_size<A>::value>{})); }; DEMO Option #2 #include <type_traits> #include <utility> template <typename A, typename … Read more