C++ :: Returning A Template Pack Nested N-dimensionally In Another Pack

Oct 28, 2014

let me jump straight to main() and my current output:

struct Base {};
struct A : Base { A() {std::cout << "A";} };
struct B : Base { B() {std::cout << "B";} };
struct C : Base { C() {std::cout << "C";} };
struct D : Base { D() {std::cout << "D";} };

[code]...

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C++ :: Parameter Pack Of Constant References

Aug 20, 2013

I have this basic prototype:

struct int_wrapper{int i;};
template <const int_wrapper&... IPack>
void display_all(const int_wrapper&, IPack...);

But when I try to compile it, the compiler says IPack is not a type on the last line. Are packs of references not allowed?

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C++ :: Unpacking Parameter Pack With Templated Predicate

Apr 20, 2014

I'm trying to generalize the following (working) code:

#include <iostream>
#include <string>
#include <cmath>
int foo (int num) {return num;}
int foo (double num) {return std::round (num);}
int foo (std::string str) {return str.length();}

[code]....

Template argument deduction failed, it says. And using pred_action<T> and pred_action<FIRST> only makes it worse.Do we need to use a visitor pattern or something like that?

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C++ :: Nested / Recursive Template Specialization

Feb 11, 2014

I'm trying to write some naive binary serialization code and wanted to cut down on repetition of logic for serializing/deserializing nested vectors or other STL containers to reduce the chance of typos etc, and thought templates might hold a solution for me.

Code:
template <typename T> void serializeField(IWriter& writer, const T& val) {
writer.write((char*)&val, sizeof(T));
}

template<typename U, typename V>
template <> void serializeField(IWriter& writer, const U<V>& collection)

[Code] ....

Is there a way to do something like this? It isn't a big deal for me to just manually write code to serialize my vectors to the needed depth, but it sure would be nice to get this working.

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C++ :: Friend Of Nested Template Class

Nov 9, 2013

Consider the following program below, which compiles without a hitch on MinGW GCC 4.8.1:

template <typename T>
class Outer {
class Nested1 {};
template <typename U>
class Nested2

[Code] .....

Is there any way I can move the definition of func outside of the class?

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C++ :: Error Returning Template Class From Member Function

Apr 30, 2012

When I do this:

// header file:
#include <list>
using namespace std;
class myClass {
list<int> myMethod();
};

// cpp file:

list<int> myClass::myMethod() {
}

In the cpp file, 'myMethod' is underlined in red and when I hover over it, it says:

"std::list<int, std::allocator<int>> myClass::myMethod()

Error: declaration is incompatible with "<error-type> myClass::myMethod()""

But when I make it as a standalone function, outside a class, with no pre-declaration, there is no problem.

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C++ :: How To Initialize Static Member Of Class With Template And Type Of Nested Class

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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C++ :: Place Nested Loop Where Nested Not Necessary?

Apr 3, 2014

I wrote this code, and everything was working well, but part of the assignment is that it must include nested loops. Once I added the nested while loop, which is basically an if statement, my life was ruined. I am trying to nest a loop in the code that will basically tell the compiler that if the value "loopVol" were to exceed the value of "final" after adding an increment, to run the program for the "final". How can I do that?

Example:

initial = 10
final = 123
increment = 10

as of now, the program would stop at 120, but I want to nest a loop that will tell the compiler to calculate at the final if this happens.

#include <iostream>
#include <iomanip>
#include <stdio.h>

[Code]......

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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 ?

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C++ :: Use Of Class Template Requires Template Argument List

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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C++ :: Partial Template Specialization With Template Class

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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C++ :: Template With A Specialized Template Class Parameter?

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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C++ ::  Writing A Function Template With Template Arguments?

Mar 14, 2014

I have a function:

template<class Iterator, class T>
void a(Iterator, Iterator, const T&);

and I want to be able to simplify calls to 'a' with calls like

a(someIteratableContainer);

instead of having to call:

a(someIteratableContainer.begin(), someIteratableContainer.end(), valueOfTheContainersElementType);

I also want to be able to generalize the function to handle any of the standard iteratable contains: array, vector, deque, whatever.

I was under the impression I could write:

template<template<class T> class U> a(U<T>& container) {
a(container.begin(), container.end(), g(T()));
}

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.

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C++ :: Use External Template With Template Specialization?

Nov 17, 2013

[URL]

#include <iostream>
struct Outer {
template<typename T>
void go() {
std::cout << Test<T>::f() << std::endl;

[Code] .....

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.

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C++ :: Passing Same Template Value To Two Different Template Functions

Dec 11, 2014

I have been trying to get a hang on templates. I have the two following functions that that could be consolidated in a single template function:

void Attractor::updateFamilies(FamiliesController *_tmp, int _counter){

center.x = ofGetWidth()/2;
center.y = ofGetHeight()/3;
attractorCounter = _counter;
if(attractorCounter == 1){

[Code] .....

NotesController and FamiliesController have the same parent. The thing that I'm trying to grasp with templates is that is could something like:

template<class TYPE>
void Attractor::updateData(TYPE* *_tmp, int _counter){
center.x = ofGetWidth()/2;
center.y = ofGetHeight()/3;
attractorCounter = _counter;

[Code] ....

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?

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C++ :: Template Class With Template Members

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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C++ :: Declare Template Type Object Inside Template Type Class Definition

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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C++ :: Vector Of Template In Template

Aug 29, 2014

Given:

#include <string>
template <class T>
class basic_container{

[Code] .....

is this possible:

#include "../basic_container/basic_container.hpp"
template <class T>
class container_vector{

[Code] .....

If not, what do I need to do to achieve my goal?

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C :: Nested For Loops

Jun 1, 2013

What output would you expect from this program?" The output was not what I expected. I've psuedo-coded this out and I'm still missing something.

Code:

#include <stdio.h>
int main () {
int numbers[10] = { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
int i, j;
}

[code]....

The output: Code: 1 1 2 4 8 16 32 64 128 256 So when I look at this first loop I see that j = 0, which is less than 10, so then the program statement should commence, which is another for loop. So in this inner for loop I see that i = 0, which is not less than j, so this loop should terminate. Then the value of j increments by 1 and the first go around of the loop has completed.

Now I see that j = 1, so this is less than 10, and the inner for loop commences once again. This time though, i actually is less than j, so numbers[1] = numbers[1] + numbers [0], or numbers[1] = 0 + 1. Now the value of i is incremented by 1 and the first go around of this inner loop has completed. Then the value of j increments by 1 and another go around of that loop has completed.

So now j = 2, i = 1, and numbers[2] ( which is 0 ) = numbers[2] + numbers[1], or numbers[2] = 0 + 1. I was expecting the output to be an array full of 1's. However this is not the case..

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C/C++ :: How To Clear Nested Stl Map

May 21, 2013

here is a nested stl map

typedef struct struct_RISCP {    
        float nSCPTotal;
        int nSCPCount;
        CString strIMEI;  
        std::map<UINT8, int> mapSection;    
    }RISCPSt;
map<stRncCellIdntyDmnType, RISCPSt>m_mapRISCP;

it occupied too much memory,i wanted to clear them(both outer map and inner map) ,some one told me you just need to call m_mapRISCP.clear(),then the mapSection (inner map) will be cleared automaticly,in other words, m_mapRISCP.clear() will clear both outer map and inner map.

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C++ :: Nested Classes And Structs

Mar 12, 2014

I'm working on a project involving nested classes and structs like this:

Code: class A {
public:class B {
public:f()
{A::C* iCanDoThis; //no errors.
iCanAlsoDoThis->root->.... //this also works fine.}private:A::C* iCannotDoThis //this is what I would like to do.
Has errors
A* iCanAlsoDoThis;};private:struct C
{..data..};

C* root;};

Is it possible make a pointer to struct C a private member of class B?

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C++ :: Nested Conditional Operations

Feb 4, 2014

So I think I am having syntactical problem with my code.

Code:
int main() {
vector<int> ivec;
int score;
[Code] ....

I get an error from my compiler on the ?10th? line (Nested condition line) that says |19|error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator<<'|

The purpose of the program is to take input and store it in a vector and then change the value to be between 1-6. I made this for the purpose of learning about nested conditional operations.

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C :: How To Make Nested Loops

Dec 7, 2013

Howi can made nested loops?

Code:

for (yax=0; yax<10; yax=yax+1) {
for (xax=0; xax<100; xax=xax+1) {
printf("%d
",yax);
}
}

way what i tired dont work. or maybe works but why this prints only zeros ?

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C++ :: Variable Nested For Loop

Mar 25, 2013

This code is used in scientific calculation for optimization problem.

Basically a particle is moving in a three dimensional space, its position is (x,y,z).

At each position, there is a fitness value associated with that position.

The fitness value is given by fitness(x,y,z) (code line 12~19).

We need to find out, when the particle moves around randomly, what is the highest possible fitness value.

To solve this, below code is used, and it produces correct result.

#define DIMENSION 3
#define MAXX 4
#define MINX 0
#define MESHsize 1
#include <iostream>
using namespace std;
float maxValue = 0.0;

[Code] ....

The output of the code:

[ fitness(0,0,0) = 0] [ fitness(0,0,1) = 1] [ fitness(0,0,2) = 4] [ fitness(0,0,3) = 9]
[ fitness(0,1,0) = 1] [ fitness(0,1,1) = 2] [ fitness(0,1,2) = 5] [ fitness(0,1,3) = 10]
[ fitness(0,2,0) = 4] [ fitness(0,2,1) = 5] [ fitness(0,2,2) = 8] [ fitness(0,2,3) = 13]
[ fitness(0,3,0) = 9] [ fitness(0,3,1) = 10] [ fitness(0,3,2) = 13] [ fitness(0,3,3) = 18]

..... so on

Answer: highest fitness = 27

Note: In this case, the values of x,y and z is integers from 0 to 3 inclusive.

For 3-dimensional space above, actually the code had run through 3 nested "for" loops.

Question: Above code works for 3-dimensional space. How to generalize the code, so that it works also for N-dimensional space, where N is an arbitrary integer?

( Note: possibly N = 30 )

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C++ :: Vector In Nested Structure

Nov 26, 2013

I have a nested record structure in C++ that contains a FileHeader record, a RecordHeader record and a DataRecord record. The last item is an array of unknown size (at compile time). I have to open a file and read the array size and then create the array.

I have worked on this for some time and can't figure out how to make it work. I know the sample data I am using has 85 records. I insert 85 into the array size and it works fine. But how do I create a dynamic array or define a vector within a nested structure?

1. What is the best (easiest) method to accomplish this (array or vector)?
2. How would it be implemented/how do you add data to it?

PreviousLogRecord.FaultRecord.push_back(field1); // does not work
PreviousLogRecord.FaultRecord[recordNumber].field1 = somedata; // works with 85 in array size.
struct LogFileHeaderRecordType {
QString field1;
int field2;

[Code] .....

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C/C++ :: Triangles With Nested For Loops?

Sep 27, 2014

So in class our teacher assigned us a program where we have to use nested for loops to creates triangles. How does the 2nd for loop print more than 1 star? since the for loop will only run the cout 1 time until it gets to the escape sequence, how does it print more than 1 star on a line? this is what is confusing me. I feel like if i can grasp the understanding of that and what the for loops are doing i can finish the rest of this program with ease

#include<iostream>
using namespace std;
int main()

[Code].....

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