So I have two classes - Dvd and DvdGroup. DvdGroup basically manages an array of dvds and provide manipulative member functions for that class. The problem is whenever I try to compile DvdGroup.cc using the command 'g++ -c Dvd.Group.cc', I get a bunch of errors all related to not having 'Dvd' declared and I'm not sure why.
Here are some errors below:
DvdGroup.h:14:12: error: ‘Dvd’ has not been declared void add(Dvd*);
DvdGroup.h:18:3: error: ‘Dvd’ does not name a type Dvd* dvdCollection[MAX_DVDS];
DvdGroup.cc: In copy constructor ‘DvdGroup::DvdGroup(DvdGroup&)’:
DvdGroup.cc:15:6: error: ‘Dvd’ was not declared in this scope for(Dvd d: dvds){
I feel like I'm missing something and they could all be fixed by one solution because they all involve having the Dvd class undeclared but I can't seem to figure out what. I was wondering if anyone could tell me what I'm doing wrong? I would really appreciate any help with fixing this.
DvdGroup.cc:
#include <iostream>
using namespace std;
#include "DvdGroup.h"
DvdGroup::DvdGroup(int n){
numDvds = n;
}
DvdGroup::DvdGroup(DvdGroup& dvds){
numDvds = dvds.numDvds;
for(Dvd d: dvds){
Dvd newDvd = Dvd;
}
}
DvdGroup::~DvdGroup(){
//code
}
void DvdGroup::add(Dvd* d){
//code
}
DvdGroup.h:
#ifndef DVDGROUP_H
#define DVDGROUP_H
#define MAX_DVDS 15
#include <string>
using namespace std;
class DvdGroup
{
public:
DvdGroup(int);
DvdGroup(DvdGroup&);
~DvdGroup();
void add(Dvd*);
private:
Dvd* dvdCollection[MAX_DVDS];
int numDvds;
};
#endif
Don't know if the Dvd header file is needed, but here:
Dvd.h:
#ifndef DVD_H
#define DVD_H
#define MAX_DVDS 15
#include <string>
class Dvd{
public:
Dvd(string, int);
void set(string, int);
Dvd(Dvd&);
int getYear();
~Dvd();
void print();
private:
string title;
int year;
};
#endif
What you need to do is to provide Dvd class definition for DvdGroup class. It is needed to know what type of symbol is this. Solution for your problem should be addition of:
#include "Dvd.h"
line to DvdGroup.h file.
Related
I'm creating a class called person right now in separate header and cpp files.
And for one of the functions I'm getting this error:
declaration is incompatible with "Person::stat Person::getStat()" (declared at line 26 of "C:...")
(Not the exact directory but you get the idea)
Here is the code in the header file:
#pragma once
#include <string>
#include <iostream>
class Person
{
public:
struct stat {
int str;
int end;
int dex;
int intel;
};
Person();
~Person();
//properties
stat getStat();
};
Here is the code in the cpp file:
#include "pch.h"
#include "Person.h"
#include <string>
#include <iostream>
Person::Person()
:age(12), height(0)
{
}
Person::~Person()
{
}
struct stat Person::getStat() {
}
I'm getting the error with the getStat() function. I've tried including the string and iostream headers in both file and also only in the header file since a similar post suggested it. Both didn't solve my problem however.
Should be
Person::stat Person::getStat() {
}
Your version declares a new struct stat which isn't the same as Person::stat.
struct stat Person::getStat() is a method that returns a stat that belongs to the global namespace, not to Person:
Person::stat Person::getStat()
Note that there is no struct here (to avoid declaring one). In C++, we don't use struct after the type has been declared.
Im having trouble with a multi-file setup. Im working in visual studio, and, for whatever reason, my friend function in my class is not being defined in main. Any help would be appreciated, thanks.
BullCow.h:
#pragma once
#include <iostream>
#include <cstdlib>
#include <stdlib.h>
#include <time.h>
class BullCow {
public:
BullCow();
friend int getWins();
static int Wins;
private:
int Attempts;
};
BullCow.cpp:
#include "stdafx.h"
#include "BullCow.h"
int BullCow::Wins = 0;
int getWins() {
return Wins;
}
BullCowMain.cpp:
#include "stdafx.h"
#include "BullCow.h"
int main()
{
srand(time(NULL));
std::cout << getWins();
return 0;
}
Note: It's an incomplete program, so some code (srand) is not used yet. I just included everything to better help figure out what's wrong.
getWins() needs at least a declaration in the .h file.
Since it's a friend, getWins() is not a member of the class, so it must be declared either directly in BullCowMain.cpp or in some file BullCowMain.cpp includes.
Add this somewhere outside of the class in your header:
int getWins();
Also, inside getwins, the return should be:
return BullCow::Wins;
Thanks #user4581301!
I've created 2 header files. ListA.h and ListN.h
They both make their own use their own unique class List. When I compile my program (even though they have no way of knowing the other exists, it says the following error)
Im pretty sure it shouldnt be a redefinition, but it obviously is. Any help is appreciated.
ListA.h
#ifndef __LISTA_H_
#define __LISTA_H_
#include <iostream>
using namespace std;
class List{
public:
List(int = 0);
List(const List&);
~List();
};
#endif
ListN.h
#ifndef __LISTN_H_
#define __LISTN_H_
#include <iostream>
using namespace std;
class List{
public:
List(int = 10);
List(const List&);
~List();
};
#endif
ListA.cpp
#include "ListA.h"
using namespace std;
List::List(int mySize)
{
//...
}
ListN.cpp
#include "ListN.h"
#include <iostream>
using namespace std;
List::List(int size)
{
//...
}
Main
#include <iostream>
#include "ListN.h"
using namespace std;
int main()
{
List myList;
return 0;
}
Both cpp files are being compiled by the compiler. Thus, when the linker goes to link the files together, it gets confused, since there are multiple List classes.
To fix this, you could use namespaces, or you cold not expose at least one of the List classes.
Alternatively, if the idea was to be able to include ListN.h vs ListA.h for configuration purposes, this is the wrong way to do so. Either you should have a #define parameter for the header, or you should find some other way, such as through #ifdef. For example (I'm not 100% sure this would compile, but you get the idea):
List.h
#ifndef __LIST_H_
#define __LIST_H_
#ifndef LIST_PARAM
#define LIST_PARAM 0
#endif
#include <iostream>
using namespace std;
class List{
public:
List(int = LIST_PARAM);
List(const List&);
~List();
};
#endif
main.cpp
#include <iostream>
#define LIST_PARAM 10
#include "List.h"
using namespace std;
int main()
{
List myList;
return 0;
}
I personally don't like this method; it is much better to just pass the value in to the constructor:
int main()
{
List myList{ 10 };
return 0;
}
When linker trying to link find the definition / symbol for List, it does found in two different obj file and hence linker givers error. In visual studio error number : LNK2005
To solve this error, either:
To fix, add /FORCE:MULTIPLE to the linker command line options
Add the classes in two different namespaces which will avoid this error.
ListN.h
#ifndef __LIST_H_
#define __LIST_H_
#include <iostream>
using namespace std;
namespace ListN
{
class List{
public:
List(int = 10);
List(const List&);
};
}
#endif
ListN.cpp
#include "ListN.h"
#include <iostream>
using namespace std;
namespace ListN
{
List::List(int size)
{
//...
}
}
Main.cpp
#include <iostream>
#include "ListN.h"
int main()
{
ListN::List myList;
return 0;
}
I'm trying to create a vector which will store objects. I have added to the header file of the class as a private data member.
I am trying to initialize this vector as being empty (so that I can add objects to it later on in the program) but when I compile this program to test, this error is returned:
...error: '_bookingVector' was not declared in this scope|
I think the problem is with my initialization list on my default constructor(_bookingVector is obviously the vector):
Schedule::Schedule() : _bookingVector()
{ }
Is my syntax wrong? Or are vectors initialized differently?
Here is my code:
Schedule.h
#ifndef SCHEDULE_H
#define SCHEDULE_H
#include "Booking.h"
#include <vector>
using namespace std;
class Schedule
{
public:
Schedule();
void AddBooking(int bday, int btime, int btrainer, int bid);
void RemoveBooking(int bday, int btime);
void DisplaySchedule();
void DisplayAvailableTimeSlots();
//For Testing
void DisplayDebug();
private:
vector<Booking> _bookingVector;
};
#endif // SCHEDULE_H
Schedule.cpp
#include "Schedule.h"
#include "Booking.h"
#include <vector>
#include <iostream>
Schedule::Schedule() : _bookingVector()
{ }
void AddBooking(int bday, int btime, int btrainer, int bid){
Booking bookingObject(bday, btime, btrainer, bid);
_bookingVector.push_back(bookingObject);
}
void DisplayDebug(){
for(int i = 0; i < _bookingVector.size(); ++i){
cout << _bookingVecotr[i] << endl;
}
}
I'm very eager to learn what I'm doing wrong and fix it.
The issue is not with the constructor, which looks fine if unnecessary1. The issue is that you have defined AddBooking and DisplayDebug as non-member functions, but these should be members in order to access other members of the class.
Modify the definitions to be in the scope of the Schedule class thus:
void Schedule::AddBooking(int bday, int btime, int btrainer, int bid) { ...
^^^^^^^^^^
void Schedule::DisplayDebug(){ ...
^^^^^^^^^^
Also, don't say using namespace std in a header file (I'd go further and say don't say it anywhere but there isn't universal agreement on that.)
1 Your default constructor does not do anything that the compiler-generated one wouldn't do. You can safely remove it.
I am farily new to C++ and I have been stuck with this problem for a few hours now. I am trying to setup the foundations for a video game related experience calculator, but I can't get past this problem.
main.cpp
#include <iostream>
#include "Log.h"
using namespace std;
int main()
{
Log Logs;
enter code here
struct ChoppableLog Yew;
Logs.initialiseLog(Yew, 60, 175);
return 0;
}
Log.h
#ifndef LOG_H
#define LOG_H
struct ChoppableLog
{
int level;
int xp;
};
class Log
{
public:
void initialiseLog(struct ChoppableLog &par1_log, int par2_int, int par3_int);
Log();
};
#endif // LOG_H
Log.cpp
#include "Log.h"
#include <iostream>
using namespace std;
Log::Log()
{
}
void initialiseLog(struct ChoppableLog &par1_log, int par2_int, int par3_int)
{
}
The error I get is
C:\Users\Murmanox\Documents\C++\C++ Projects\CodeBlocks\Class Files Test\main.cpp|11|undefined reference to `Log::initialiseLog(ChoppableLog&, int, int)'|
I can post more details if necessary.
You have to define Log::initialiseLog with its full name, like so:
void Log::initialiseLog(struct ChoppableLog &par1_log, int par2_int, int par3_int)
{ }
What you are doing is defining a new, free function of the name initialiseLog instead of defining the member function of Log.
This leaves the member function undefined, and, when calling it, your compiler (well, technically linker) will be unable to find it.
The definitions of functions in a header file should specify the scope. In your case, you should define initialiseLog() function in your cpp file as follows:
void Log::initialiseLog(struct ChoppableLog &par1_log, int par2_int, int par3_int)
{
}