templates

问题 For our Code Igniter application we are loading all of our javascript just before the closing body tag. so in our controllers we have $this->load->view('head', $this->head); $this->load->view('main_view_for_controller', $data); $this->load->view('foot', $this->foot); And in the foot view we have a bunch of <script src="master.js"></script> tags. These include jQuery jQuery-ui shared-functions Now this works great, until you think about JS used only on specific pages, or inline js. You can't

问题 For our Code Igniter application we are loading all of our javascript just before the closing body tag. so in our controllers we have $this->load->view('head', $this->head); $this->load->view('main_view_for_controller', $data); $this->load->view('foot', $this->foot); And in the foot view we have a bunch of <script src="master.js"></script> tags. These include jQuery jQuery-ui shared-functions Now this works great, until you think about JS used only on specific pages, or inline js. You can't

问题 Why isn't there an array template specialization for std::allocator<T[]> in c++14? When playing around trying to specialize std::allocator<T[]> myself I hit a dead-end when implementing the construct() and destroy() method. Is this the reason? Why then have construct() and destroy() part of std::allocator<>? template <T> class allocator <T[]> { // ...most is similar for std::allocator<>... template <class U, class... Args> void construct( U *p, Args&&.. args) { // what to write for array

问题 Why isn't there an array template specialization for std::allocator<T[]> in c++14? When playing around trying to specialize std::allocator<T[]> myself I hit a dead-end when implementing the construct() and destroy() method. Is this the reason? Why then have construct() and destroy() part of std::allocator<>? template <T> class allocator <T[]> { // ...most is similar for std::allocator<>... template <class U, class... Args> void construct( U *p, Args&&.. args) { // what to write for array

问题 Why isn't there an array template specialization for std::allocator<T[]> in c++14? When playing around trying to specialize std::allocator<T[]> myself I hit a dead-end when implementing the construct() and destroy() method. Is this the reason? Why then have construct() and destroy() part of std::allocator<>? template <T> class allocator <T[]> { // ...most is similar for std::allocator<>... template <class U, class... Args> void construct( U *p, Args&&.. args) { // what to write for array

问题 Why isn't there an array template specialization for std::allocator<T[]> in c++14? When playing around trying to specialize std::allocator<T[]> myself I hit a dead-end when implementing the construct() and destroy() method. Is this the reason? Why then have construct() and destroy() part of std::allocator<>? template <T> class allocator <T[]> { // ...most is similar for std::allocator<>... template <class U, class... Args> void construct( U *p, Args&&.. args) { // what to write for array

问题 #include <string> template<typename T, typename C, typename CR> void f() { typename T::size_type* p1{}; // ok typename CR::size_type* p2{}; // error typename C::size_type* p3{}; // Does the C++ standard allow this? } int main() { f<std::string, const std::string, const std::string&>(); } Do const T and T have no difference when taking its nested type? 回答1: Indeed, the "nested types" are the same. A type qualified with const and/or volatile is a "version" of the unqualified type ([basic.type

问题 while in visual c++ the code below is accepted, g++ will generate the error: "class Derived does not have any field name Base" which is following the standard? template <class T> class Base { public: Base(){}; }; template <class T> class Derived:public Base<T> { public: Derived():Base(){} }; BTW: both accept Derived():Base<T>(){} so meantime, I will follow gcc 回答1: MSVC++ is not correct. Base is a template, not a type. Note that in the usual case, Base is looked up in the scope of Derived<T>

问题 I have a template that calls a member function. How do I check with static_assert that the method exists? struct A { }; struct B { int foo() { return 42; } }; template <typename T> struct D { static_assert(/* T has foo */, "T needs foo for reasons"); int bar() { return t.foo(); } T t; }; int main() { D<A> d; std::cout << d.bar() << std::endl; return 0; } I know this will just generate a compiler error that A does not have foo but I would like to check and give a better error output using

问题 I'm trying to write a bit of code that requires me to have a lot of std::array s in a container class. These arrays are all of varying sizes (all consecutive from 2-16, if that matters), and there is exactly one of each size. I want to put them in a container class, and be able to access them with templates. It's probably easier to explain with code. I want something like this: class ContainerClass { public: // I want to declare some number of arrays right here, all of different // sizes,