lets say we have a valid class with full implementation, X. can this class be declared as forward in Y header file:
Code: class X;
class Y{
X* m_X;
}
but still be used as regular in the cpp file?
Code:
#include "Y.h"
#incldue "X.h"
T Y::function(){
m_X->doSomething();
}
visual studio prevents me from doing it , I wonder if the standard also says so.
How can I forward declare an inner class?
I currently have this:
Code:
class Enigma
{
public:
Enigma()=delete;
Enigma(char r1,char r2,char r3,char r4, char r5, char r6, char r7, char r8, char r9, char r10);
~Enigma(){delete[] R;}
Enigma(const Enigma& rhs)=delete;
Enigma& operator=(const Enigma& rhs)=delete;
[Code]...
I'd like to be able to define Rotor outside of Enigma, but the compiler complains about incomplete types.
I have a header file in which we include vector at the top. But we want to remove that include. On doing so I get compilation errors as the header file uses std::vector<> at several instances in header file so I have to forward declare the vector to solve this issue.how i can do it.
Header file :
#ifndef MKLMulticlassOPTIMIZATIONBASE_H_
#define MKLMulticlassOPTIMIZATIONBASE_H_
#include <shogun/lib/config.h>
#include <vector>
#include <shogun/base/SGObject.h>
namespace shogun {
[Code]...
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;}
}
Where the template is not for a specific "type".
I read in another forum that it is bad practice to declare static variables in a header file? Is that true and if so why.
View 1 Replies View RelatedI am working on an assignment in which i have to perform th following task
myClass itsObject1,itsObject2;
itsObject2=5000+itsObject1;
I have defined overloaded operator as follows in the header file but in the cpp file of the class it gives error.
friend vli &vli::operator + (int &a,vli &obj);
How to define it in cpp file of my class?
What is the right syntax for implementing the .cpp of a template class?
Consider this LinkedList.h file:
Code: #include<iostream>
#include"Iterator.h"
template <class T>
class LinkedList {
[Code] ....
How should the implementation for the LinkedList constructor, for example, should look like in the LinkedList.cpp file?
I tried this:
Code: #include "LinkedList.h"
template <class T>
LinkedList<T>::LinkedList<T>() {
// constructor
}
LinkedList<T>::~LinkedList<T>() {
// destructor
}
But the compiler wouldn't accept it.
I have been working a project in C++. I have TTTMain.cpp file that has all the function calls, TTTFuntions.cpp that has all the functions, I have TTT.h file that has all the prototypes and variables and additionally I have Winner.h that has enum class Winner declaration in it. Here is my block of codes:
Winner.h file:
#ifndef winner
#define winner
enum class Winner {
[Code]....
My question is when I compile this gives me error on
Winner gameSquares[] = { Empty, Empty,Empty, Empty, Empty, Empty, Empty, Empty, Empty };
with saying "invalid use of non-static data data member" and It says "Empty was not declared in this scope."
I know calling enum is very very trick.
I've been wondering about something for a while:
Is it possible to declare a struct/class, in a cpp file, designed for local use, but with internal linkage?
The usecase is that every once in a while, I want to wrap "startXXX+endXXX" function pairs in a simple RAII struct. I just declare the struct in my cpp and use it once.
However, if I do this, (AFAIK), the compiler will generate an entry in the link table, which means I could potentially have link conflicts if I declare the same struct twice in two different cpp files.
Unless I'm mistaken, since the struct is declared in the same cpp that it is used, I wouldn't need external linkage. Is there a way to avoid it?
I wrote a simple date class and could not get it to work until I put all the code in main(). Then it worked like a charm. I have not been able to create a separate .cpp file and get it to work with my existing main().
I tried to follow [URL] which is a closed article, with no success. I tried every combination I could think of and was unable to compile without error. (Linux Mint 17,code::blocks 13.12, G++ 4.8.2). I did finally get it to work by putting *all* my code in the .h file and #including the .h file (and nothing else) in the .cpp file. This is not how it's supposed to work.
This is unbelievable! I just tried this on another computer, same OS same version of Code::Blocks and G++.
In the code given below using turboc++ 3.0(really old i get it but its school rules)
#ifndef emoji_h
#define emoji_h
class emoji//here for some reason {
};
#endif
error i get :line 3 declaration syntax error why and how to correct it?
I'm trying to use a class member to initialize the dimension of a matrix. I have two issues. Here is the code (.h) simplified :
#include <vector>
#include <array>
#include <typeinfo>
template<typename T, std::size_t N>
struct md_vector {
[Code] ...
error: invalid use of non-static data member ‘OptimalSamplingStrategy::_nbMorph’|
I can't use a class member directly in the header file (here _nbMorph).
It was an issue I got before and that I didn't solve as I succeed in finding other ways. I don't think it's possible here.
Here's my class/header, and Visual studio Output.
Injection point/instantiation.
int main() {
Player player;
Call to a public method:
while(!isWin("x", board) && !isWin("o", board) && whoGoesFirst == "p") {
printBoard(board);
board = player.playerTurn(board);
[Code] .....
Output:
1234
1
1> Player.cpp
1>c:users
sccdocumentsvisual studio 2012projectsprog 2100 - assignment 1prog 2100 - assignment 1player.h(10): error C2143: syntax error : missing ';' before '<'
1>c:users
sccdocumentsvisual studio 2012projectsprog 2100 - assignment 1prog 2100 - assignment 1player.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:users
sccdocumentsvisual studio 2012projectsprog 2100 - assignment 1prog 2100 - assignment 1player.h(10): error C2238: unexpected token(s) preceding ';'
I have a small class with a static int data member. I want to zero init it. I am thinking that making a .cpp file with only one line seems too much, isn't it?
So, can I do it inside the the header file? The variable is going to enumerate how objects were created (so any alternative will do).
I have a header file with a bunch of functions. I want to create a thread using the <threads> package and am using
void myclass::functionX() {
}
void myclass::function() {
std::thread tr(myclass::functionX);
}
I am getting the error "no instance of std::thread::thread matches the argument list argument types are (void());
I am currently learning OOP, and I can't figure out what the problem is with my header file. The rest of the program complies fine though. I am using g++ on UNIX.
myClass.h:9:23: error: Rectangle.h: No such file or directory
myClass.h: In function ‘int main()’:
myClass.h:13: error: ‘Rectangle’ was not declared in this scope
myClass.h:13: error: expected `;' before ‘rect’
myClass.h:14: error: ‘rect’ was not declared in this scope
Code:
myClass.h
/* This header file contains, The main function for my rectangle class program.*/
#include "Rectangle.h"
using namespace std;
int main(){
Rectangle rect;
rect.displayMaxRectangles();
rect.process();
rect.summary();
[Code] .....
I am currently doing the assignment about linked list. Here are some details information about what I am doing.. This program is C++ and should run on Visual Studio 2010. And it contains three file, two datastructure header and one main cpp file.
This program is trying to arrange and show some sports records. The main program which contain the functions such as reading the result text file(each result text file contain several records of athletes), removing a file, arranging the totalresult and printing it out. And the main program is already given and I cannot overwrite it.
But when I finished and try to build the solution and run it, I am not able to run the program and it give me somethings like these...
warning C4172: returning address of local variable or temporary
error C2248: 'Datastructure1::Datastructure1' : cannot access private member declared in class 'Datastructure1'
see declaration of 'Datastructure1::Datastructure1'
see declaration of 'Datastructure1'
This diagnostic occurred in the compiler generated function 'Result::Result(const Result &)'
And I have tried to comment each function part of the header file and see if can run or not. But I still fail to do so. Here are my codes...
#ifndef DATASTRUCTURE1_H
#define DATASTRUCTURE1_H
class Datastructure1 {
Public:
Datastructure1( );
[Code] ....
There are two header files and look quite long. They are all some linked list functions . I have read and learn linked list data structure before I complete this programs. However, when I complete the functions required, the function cannot be compile....
I am a beginner with C++, taking a class right now. The lab this week is to create a user defined class and have it accesses in a separate .h header file from the main.
I think I'm finding my way through it, but I'm getting a complie error that makes no sense to me:
1> Resistor.cpp
1>c:users omdocumentsschoolcomp 220week 2lablab 2.2lab 2.2
esistor.h(11): error C2146: syntax error : missing ';' before identifier 'resistor'
1>c:users omdocumentsschoolcomp 220week 2lablab 2.2lab 2.2
[Code] .....
Here is the first portion of the .h file:
#include <iostream>
#include <iomanip>
#include <Windows.h>
#include <math.h>
#include <string>
class CResistor{
double res1, res2, res3, percentage, Nominal, Tolerance;
[Code] ....
I am using OpenCASCADE environment to read STL file! I face a problem, with forward declaration error with the following
void StlReadIn::STL_Import() {
std::string FileName;
std::cout<<"
Enter the file name
";
std::cin>>FileName;
[Code] .....
Error message:
stlreadin.cpp:26:47: error: invalid use of incomplete type ‘struct StlMesh_Mesh’
/usr/local/oce-0.9.1/include/oce/Handle_StlMesh_Mesh.hxx:23:7: error: forward declaration of ‘struct StlMesh_Mesh’
I have an EDI file whose structure is given below. This file has multiple records, each record contains a header (e.g EDI.DD.0000000001.20130809), then contents (i.e multiple paragraphs of text) and then footer (e.g End of Report/No EDI Activity). I have to read that entire file using regular expression using three groups.
I am using following regular expression to read the file.
(?<header>[A-Z]{3}.[A-Z]{2}.[0-9]{10}.[0-9]{8}) | (?<footer> (EndsofsReport|NosEDIsActivity)) |
(?<content>(?<=k<header>).*(?=k<footer>))
That expression reads the "header" and "footer" in respective groups properly but didn't pick the contents between header and footer in "contents" group.
I have changed the font of header and footer in below file to understand the format. I am using asp.net 3.5 framework.
//------------------Start of EDI File---------------------//
EDI.DD.0000000001.20130809
ORIGINATOR INFORMATION Company Name: UNITED HEALTHCAR Identification: 9024125001 Originating DFI: 002100002
RECEIVER INFORMATION Receiver Name: HEALTH & WELLNESS DFI Account Number: 0000000000000001 Receiving DFI ID: 434343430 ID Number: Transaction Type: 22 Deposit
ORIGINATOR INFORMATION Company Nam
[Code] ....
I have written my program and it works when I keep everything in the header files, and then have my main. I am now splitting them up into implementation files, but Eclipse keeps giving me errors. It gives me error at every opening brace of the constructor and functions. It says on all of them "Redefinition of (name of constructor or method), Previously declared here." What am I doing wrong, because it works in the header file?
#include "KeyValuePair.h"
template<typename Key,typename Value>
KeyValuePair<Key,Value>::KeyValuePair()
[Code] .....
I wanted to share the value of a variable from Sender Program to Receive after program and want to calculate difference between send and receive. After studying Header file concept I program following three.
Now I am struck. How to to compile? I link all these file. I used following method:
Code:
gcc Sender.c -o Sender Sender.h
gcc Receiver.c -o Receiver Student.h
Then I run Sender and after that Receiver.I per my knowledge, Receiver should give difference but it gives error :
Code:
Receiver.c: In function "main":
Receiver.c:10:42: error: "Send" undeclared (first use in this function)
printf(" Total Receive is %d
",Receive-Send);
Code:
Sender.c
#include <stdio.h>
int Send ;
void main(){
[Code] ....
I am beginner in c++ language. i'm use visual studio 2010 ultimate. the problem is i can't add c++ file(.cpp) and header file(.h).
Here the screenshot : [URL] ....
I made my header file. If cpp file with definitions is in project compiler knows it has to be linked, but if it's not compiler doesn't know. If I include standard library or boost I don't have to manually link cpps. How to do so including my header automatically links cpp? Maybe problem is with something else?I use VS 2013.
View 4 Replies View RelatedMy socket.cpp program got error. it showed "socket.h: no such file or directory". I had put my header file (socket.h) in the same place with my source file.
View 1 Replies View RelatedI have a class "SelectionGroup" which derives from a class "RMFObjectContainer". RMFObjectContainer has member variables of type SelectionGroup, so I need to include SelectionGroup.h in the header of RMFObjectContainer.h.
However, since SelectionGroup needs RMFObjectContainer to derive from it, I get a typical case of mutual inclusion.
I then proceeded to put the forward declaration
class RMFObjectContainer;
instead of
#include "RMFObjectContainer.h"
into the header of SelectionGroup.h.
However, I receive the following compile error (MSVC2010), as if the forward declaration was unseen:
#pragma once
#include "Solid.h"
#include "Entity.h"
#include "SelectionGroup.h"
[Code]....