C++ :: how To Declare Template Function Inside Template Class
Dec 5, 2013
I'm trying to implement a simple template array class, but when i came into the operator< i actually have to use a template :
my code is something like :
template<typename _Type, std::size_t _Size>
class array {
public :
[Code] ......
but i am having an error of shadows template param 'class _Type' is it w/ the name conflict between the array template parameter and the function template parameter ?
/** This class build the singleton design pattern. Here you have full control over construction and deconstruction of the object. */ template<class T> class Singleton
[Code]....
I am getting error at the assertion points when i call to the class as follows:
i want to use a class to print data stored as vector or array with different data types. i also want the print function two take more than one vector or array or combination of both so that they can be written to file as two columns. so i wrote the following class:
right now it has only one member function for printing two vectors. later i'll add additional functions as required.
note: there has to be template functions inside the class i also want the object to be global so that i need not pass it as an argument to other calling functions
then i want to call this template function in another ordinary function written in a seperate cpp file
these function declarations are put in a header file. so i need know whether i should put the declaration of the template function in the header to use the function in different functions
i want to use a class to print data stored as vector or array with different data types.
i also want the print function two take more than one vector or array or combination of both so that they can be written to file as two columns.so i wrote the following class:
right now it has only one member function for printing two vectors. later i'll add additional functions as required.
note: there has to be template functions inside the class / i also want the object to be global so that i need not pass it as an argument to other calling functions
then i want to call this template function in another ordinary function written in a seperate cpp file these function declarations are put in a header file. so i need know whether i should put the declaration of the template function in the header to use the function in different functions.
i hit the point where i have two class templates that are dependent on each other (in detail, class a stores a pointer of class b), creating a cyclic include issue.
Usually i resolve this with a forward declaration, but i cant seem to figure out how to do it with a template class.In fact, ( i think) i got it to work for this :
Code: template<typename T> class a { public: T x; }
but not for this:
Code: template<int b> class b { public: int getb(){return b;} }
Error1error C2955: 'DoubleLinkedListInterface' : use of class template requires template argument listdoublelinkedlist.h10 Error2error C2244: 'DoubleLinkedList<T>::DoubleLinkedList' : unable to match function definition to an existing declaration doublelinkedlist.cpp7
Error3 .cpperror C2244: 'DoubleLinkedList<T>::~DoubleLinkedList' : unable to match function definition to an existing declaration 12
.h
#pragma once #include "DoubleLinkedListInterface.h" #include "Node.h" #include <iostream>
I have a generic template class with another template in one of its types. Now I want to specialize one of its methods for a particular (template) class, which leads to a compile error, however.
GCC ends with: :35:27: error: type/value mismatch at argument 2 in template parameter list for ‘template<class Type, template<class> class O> class Foo’ :35:27: error: expected a class template, got ‘Obj2<Type>’
What is wrong with the specialization? Can it even be achieved and how (if so)?
how I want the code to look. Only problem is it doesn't work (Line 11). I have some experience with templates but I'm not a pro.
Basically I want the "Channels<3>" to be a type that I can use to specify a Cable with similar to vector<float/int> it would be Cable<Channels<2 or 3>>.
What have I messed up with the syntax?
#include <iostream> #include <vector> using namespace std;
where 'g()' returns an object of the element type. However, the compiler is claiming, no matter how I write a call to the overload, the original template is selected and/or the overload is invalid, depending on the various ways I attempt to write said overload.
I have this class templates And This UML.I have to write this function +operator=(source: Array<ElemType, SIZE>): Array<ElemType, SIZE> but I do not know how to start the declaration / or start the function. I have to return a template but I do not know how to do it,
I want to have a template function that is a member of a class. Is this possible? This code snippet is how I would think the syntax would go, although it doesn't compile. How would I achieve the same effect?
Code: class myclass { public: int member ; } ; template <typename T> void myclass::func( T& arg )
Based on the arguments passed to foo, the compiler can deduct the type T. But on the other hand, when we use a class template, we always need to specify the type, for example,
Code: template<class T> struct sum { static void foo(T t1, T t2) { } }; sum<int>::foo(1,3);
Here we can't call sum::foo(1,3), otherwise we get compiler errors. My question is why the compiler can't deduct the type based on the arguments passed to foo? In addition, if we call function template foo like this,
Code: foo(1, '3');
Then we get compiler errors. We need to specify the type like foo<int>(1.'3'). Since '3' can be always treated as integer, why we need to specify the type here?
I have in the past written code for templated functions where one function argument can be either a function pointer or a Functor. Works pretty straightforward.
Now I am in a situation where I am actually trying to pass a function pointer as template argument to a class. Unfortunately this does not work, I can pass the Functor class but not the function pointer. Below code illustrates the issue:
The idea is to have the definition of the Record class simple and readable and have a maintainable way to add auto-conversion functions to the class. So the lines I commented out are the desirable way how I want my code to look. Unfortunately I could not come up with any way that was close to readable for solving this.
I'm trying to write a function for receiving messages, so my classes can communicate with each other. The only issue I get is a compile error asking me to define the base parameter as one of the derived instances. I tried using a void* to fill the need, but then I lose the initial type, which I need to check for. How might I go about writing a generic object for this?
Here's my code:
template<class Object> class State { public:
[Code].....
Should I just have all of the objects inherit in the order of Object >> GenericObject >> DerivedObject?
I have a class "Result" with a single template function Set(const std::string& arName, T& val) and a specialization of this function Set<Real>(const std::string& arName, Real& val) where Real is a typedef for double. The class is in a shared library and I use it in my main program. If I do result->Set<GLOBAL::Real>("U", 100.0); the wrong template function is called!
I check this by the output with std::cout.
Maybe it's a problem with the typedef.
If I link the object file of the Result class directly to my main program (no shared library), it works.
I wanted to add that the template argument is needed because its a "special case" but if that doesn't work what would be the next best way to solve this problem. I want to be able to declare the const size of the array outside the class far removed from it actually. I'm actually going off this page
I have tried several variants on this code to no avail. Outer is in a header, along with the extern template statements, and the specializations after main are in their own cpp file. Main is in a different cpp file.
What do have to do to make this work? I cannot bring the definitions of f() into the header, and they will be different for different template parameters. Ideally, I want Test to remain a private member of Outer, though this can change if it's the only option.
And then have another template function declaration for all the attractor functions where I pass the same template value as in the first one.
As you can see, I'm calling another functions inside called attractors(_tmp). I know that one way around it could be to get rid of that function and just do all the logic inside of each if statement. Is there any way to pass the same template function parameter within a template function parameter?
std::cout << "Hello C++ programmers!" << std::endl;
I am trying to create a LinkedList (and then, an ADT stack; // yes, I cannot use the STL stack because the teacher won't let me), and I am getting some weird error when I create a ListNode and declare LinkedList (which has the ListNodes!) a friend of it.
I have tried forward-declaring LinkedList in the ListNode.h file, but I get this error:
error: 'ListNode' does not name a type
Are there any other possible solutions to this problem; // without having to resort to crazy stuff like having a .h file #include a .cpp file, or even declaring and defining ALL OF MY CODE in the .h files???