C++ :: Template Class Inheriting A Templated Class
Dec 9, 2014
I'm making a minimal spanning tree class that inherits a graph class, both are templated. This is my mstree.h so far:
#ifndef _MSTREE_H_
#define _MSTREE_H_
#include "graph.h"
namespace MSTreeNameSpace
[Code]...
and I keep getting these errors:
mst.h:9:25: error: expected template-name before ‘<’ token
class MST : public Graph<T>
^
mst.h:9:25: error: expected ‘{’ before ‘<’ token
mst.h:9:25: error: expected unqualified-id before ‘<’ token
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Jan 21, 2013
I want to specialize a particular function for Integer datatype inside a class template. My XX.h will be
namespace ZZ {
template <class T>
class XX {
void doSomething(T x);
};
}
provide me XX.cpp which has template specialization for the function doSomething on Integer datatype.
I tried the following in XX.cpp
#include "XX.h"
using namespace ZZ;
template <class T>
void XX<T>::doSomething(T x) {
[Code] ...
But this code is not working.
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Apr 21, 2014
#include "IMyIntData.h"
class MyIntData : public CPMUnknown<IMyIntData>
{
I need to know what this syntax means (including MyIntData in angular brackets after parent class name) where IMyIntData is the Interface from where MyIntData is derived.
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Oct 23, 2013
I would like to define a templated class while implementing default value on templated arguments. I don't know how to do that with string templated variables.
For exemple:
Code:
template <class T>
class A {
public:
A() { version = ???? }
std::string_base<T> version;
};
I don't want to pass the default value as parameter of the constructor. how I can do this?
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Feb 3, 2013
I'm trying to template the return type for this function (component), I've looked around for example code but there doesn't seem to be any exactly like what I want.
Entity.hpp
class Entity {
public:
Entity();
unsigned int id = 0;
Component& addComponent(std::string);
[Code] ....
Error : 'ent1.component<HealthComponent>' does not have class type
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Jan 30, 2014
I have a variadic base class with a pure-virtual function per type:
Code:
template <typename ... Types>
class Base;
template <typename T, typename ... Types>
class Base<T,Types...>: public Base<Types...>
{
public:
using Base<Types...>::doSomething;
[Code] ......
Now, I'd like to inherit from it using another variadic class, which provides implementations of doSomething(), but I run into trouble --- where do I indicate it derives from Base?
Code:
template <typename ... Types>
class Derived;
template <typename T, typename ... Types>
class Derived<T,Types...>: public Derived<Types...>
[code]....
I see two possible approaches:
First, virtual inheritance *might* get me what I want, but I don't know how bad a performance hit that might be.
Second, I could do some magic where the full set of types is captured in a tuple at the lowest level and continually passed up, then re-expanded in the base case to indicate Base inheritance. However, I'm not sure if that can be done in an unambigious manner; I can't have two variadic packs at once (Types... and the tuple contents), and I'm not sure if there's a way to use enable_if to check if an arbitrary template type is any kind of tuple.
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Mar 9, 2012
I just read and have known for a while that classes are private (members and inheritance) by default and structs are public. But my question then comes what if.. a struct inheriting from a class or a class inheriting from a struct?
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Oct 7, 2014
I've this variadic template class implementation:
// Predefine template delegate factory
template < typename R, typename... Args >
class brGenericDelegate ;
// C++11 template alias to announce functor definition
template < typename R, typename... Args >
using brGenericDelegateType = std::function< std::shared_ptr<R>(Args...) > ;
[code]....
This template works fine for me. Now I have to compare, if the functors of the generic templates are equals ore not. Actually I see no way to reach this aim, because I've to cast the brDelegate on each request.
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Apr 19, 2014
I'm trying to make an templated class of List and trying to make a list of Students(another class) which I made. Its not working.
Code seems to work fine for pre-defined data types but it crashes when it comes to students. I also want to run sort function on list of students.
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Mar 12, 2012
Can I determine if a templated class has a particular constructor, in my case using a string within function to which T is used?
Code:
template<class T>
void MakeObject(std::vector<T>& dataVector)
{
std::string str "con string,Joe,24";
// catch if T has string constructor
T someObject(str); // T someObject should have constructor from string
dataVector.push_back(someObject);
}
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Oct 7, 2014
How to initialize a static member of a class with template, which type is related to a nested class?
This code works (without nested class):
#include<iostream>
using namespace std;
struct B{
B(){cout<<"here"<<endl;}
};
template<typename Z>
[Code] ,....
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Nov 30, 2013
I am trying to pass a class as a type to a template class. This class's constructor needs an argument but I cannot find the correct syntax. Is it possible?
Here is an example of what I described above. I did not compiled it, it is for illustrative purpose only. And of course argument val of the myData constructor would be doing something more useful than simply initializing an int....
template <class T>
class templateClass {
templateClass() {};
[Code]....
My real code would only compile is I add the myData constructor:
myData () {};
and gdb confirmed that it is this constructor that get called, even with dummy(4).
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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 ?
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Nov 6, 2013
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>
[Code]....
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May 27, 2013
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.
Here is the example:
#include <stdio.h>
template<typename Type>
class Obj1 {
public:
void ID() { printf("Object 1, size = %zu
[Code] .....
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)?
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Nov 2, 2014
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;
[Code].....
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Feb 9, 2015
I have a class like this
PHP Code:
template<class X>
class A {
X m_x;
public:
X* foo();
X* bar();
//others are not related to X
};
I would like to get rid of
PHP Code: template<class X>
For class level but still use it for members. Like this
PHP Code:
class A {
X m_x;
public:
template<class X>
X* foo();
template<class X>
X* bar();
//others are not related to X
};
However, I am still stuck at
PHP Code: X m_x;
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Oct 12, 2013
Let me put it into the code snippet:
/**
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:
osgOpenCL::Context *cxt = osgOpenCL::Singleton<osgOpenCL::Context>::getPtr();
I tried commenting assertion statements and then the debugger just exits at the point where getPtr() is called.
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Feb 4, 2014
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.
Here is my header-file code for both classes:
ListNode.h
#ifndef LISTNODE_H
#define LISTNODE_H
#include "LinkedList.h"
[Code]...
The errors I am getting are:
error: 'LinkedList' is not a class template
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???
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Mar 3, 2013
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,
UML
Array<ElemType, SIZE>
-elements: ElemType[SIZE]
+Array()
+Array(source: Array<ElemType, SIZE>)
+operator=(source: Array<ElemType, SIZE>): Array<ElemType, SIZE>
+operator==(other: Array<ElemType, SIZE>): Boolean
+operator!=(other: Array<ElemType, SIZE>): Boolean
<<L-value>>+operator[](index: Integer): ElemType
<<R-value>>+operator[](index: Integer): ElemType
[code]....
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Feb 3, 2013
I want to use a template function of a class.
This is my code:
#include "Comparison.h"
#include <iostream>
using namespace std;
int main(int argc, char** argv) {
Comparison c;
[Code] ....
But I get the error message:
main.cpp:10: undefined reference to `int Comparison::max<int>(int, int)'
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Mar 22, 2013
refer to the code below, the attribute class is created with the value type and default value, but why it doesn't work for std::string?
#include <string>
#include <iostream>
using namespace std;
[Code].....
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Sep 13, 2014
The code below references to a header file and implementation .cpp file, which are not important. My question is what is the proper way to use a constructor in a main file. I have been getting "invalid use of" errors when using letters.Pair(a,b), where Pair(T a, T b) is a constructor that accepts arbitrary type T of variables 'a' and 'b'. So I played around a bit and suddenly found a syntax that works. I need verification for the syntax below:
#include <iostream>
#include "pair.h"
#include "pair.cpp"
[Code].....
Are the comments with the asterisks correct? As in this is always the way you initialize and assign? So letters.Pair(a, b) is not the right way to use constructors?
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Jun 3, 2014
I have the following class header in library, but when i initialize in main the class, i have an error unresolved external symbols. So the class is not exported as it should.
Code:
template <typename Key, typename Value>
class UTILITIES_EXPORT MyMap : public QMap<Key, Value>
{
public:
MyMap() : QMap<Key, Value>() { }
[Code]....
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Dec 5, 2013
The following program is designed to demonstrate class templates. The program will evaluate postfix expressions input to the console by pushing them in a stack, and then popping them and evaluating them as such, (ex. entering 3 4 + would equal 3+4 = 7).
The code is below. We are not to modify it, but to fill in the blanks, the places filled in indicated with two asterisks for a line, and one on each side for a part of a line. If I didn't know what to enter (if anything), I put three ?s. If you want to copy and compile for yourself, look for all the *s and ?s.
1) I'm turning up all sorts of errors in the main program file (prog5.cpp) having to do with stacktype.cpp. It has been removed from the program, as it is included at the end of stackType.h. Most of them are "cannot convert 'this' pointer from StackType to StackType<stack> &'. How do I fix that?
2) The program supposedly lacks a default constructor, and it keeps turning up that 's' is an array of unknown size (do I call StackType or stack or what?).
stackType.h Code: #pragma once// Catherine Stringfellow and Trey Brumley
// A Stack is a data type, which stores values in an order where values are added to the top of the stack when pushed,
// and when popped, remove and return the value from the top of the stack.
// Class specification for Stack ADT in file StackType.h
using namespace std;
static const int MAXITEMS = 50;
[code].....
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Apr 25, 2013
I have a list of numbers in an array created by a class template
Code:
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
using namespace std;
const int CAPACITY = 20;
template <class T>
class A
[code].....
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