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!
Related
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.
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)
{
}
Recently I've been learning how to create methods within classes so that I only have to write a method once and for each of that class I instantiate I can call the one method and it will work only on the variables of the object that called it, I know how to do this when only using main.cpp and no headers however I am confused on how I should be writing this when I use a class header and cpp.
I have a sample of code similar to what I want to achieve:
#include <iostream>
using namespace::std;
class Object
{
public:
int stuff;
void manageStuff();
Object();
};
void Object::manageStuff()
{
stuff++;
}
Object::Object() : stuff(0) {}
Object object1, object2;
int main() {
for (int i = 0; i < 10; i++)
{
object1.manageStuff();
object2.manageStuff();
cout << object1.stuff << "\n";
cout << object2.stuff << "\n";
}
}
This works fine and allows me to have two instances of Object and a method that works independently for each instance, this is my current project:
main.cpp:
#include <iostream>
#include "Test.h"
using namespace std;
int main()
{
Test test;
for (int i = 0; i < 10; i++)
{
test.count(); // Here's my error "undefined reference to Test::count"
}
return 0;
}
Test.cpp
#include <iostream>
#include "Test.h"
using namespace std;
Test::Test()
{
//ctor
}
Test::~Test()
{
//dtor
}
Test.h
#include <iostream>
#ifndef TEST_H
#define TEST_H
class Test
{
public:
Test();
virtual ~Test();
void count();
int counter();
};
#endif // TEST_H
and finally TestFunctions.h
#include <iostream>
#include "Test.h"
#ifndef TESTFUNCTIONS_H_INCLUDED
#define TESTFUNCTIONS_H_INCLUDED
void Test::count()
{
Test::counter++;
std::cout << Test::counter;
}
#endif // TESTFUNCTIONS_H_INCLUDED
I'm sure that there will be something that's very obviously wrong to a more seasoned programmer and I'm about to look a bit thick but any help would be greatly appreciated
Thanks!
I would suggest getting rid of TestFunctions.h, and adding the implementation of Test::count() to Test.cpp. Currently, the TestFunctions.h header is not included anywhere, so you have no access to the definition from main.
You defined (i.e. implemented) Test::count() in a header file (TestFunctions.h), but you never included it anywhere so the code there is not compiled.
You should change it to be in a .cpp file, compile it and link it with the other source files. There's no reason why not to place it in Test.cpp.
Rename TestFunctions.h into TestFunctions.cpp, make it compiled same way as main.cpp and linked.
Alternatively, include TestFunctions.h somewhere, e.g. main.cpp
In my Function.h file:
class Function{
public:
Function();
int help();
};
In my Function.cpp file:
#include "Function.h"
int Function::help() //Error here
{
using namespace std;
cout << "Help";
return 1;
}
In my Main.cpp
#include <iostream>
#include "Function.h"
using namespace std;
int menu(){
Function fc;
fc.help();
return 1;
}
int main(int args, char**argv){
return menu();
}
Error is : ‘Function’ has not been declared
Can anybody tell me why? Thank you.
I tried like this and the problem is solved, but I dont really understand why:
In Function.h file:
I use
class Function{
public:
int status;
Function():status(1){}
int help();
};
instead of the old one
class Function{
public:
Function();
int help();
};
All your include statements are missing the #:
#include "Function.h"
^
Everything else looks fine, though you need to also #include <iostream> in Function.cpp since you're using cout.
Here is the Function.cpp that I got to compile and run:
#include "Function.h"
#include <iostream>
int Function::help() // No error here
{
using namespace std;
cout << "Help";
return 1;
}
Function::Function()
{
}
I had a similar problem. Make sure that you only have the required header files. I had two header files both including each other and it spit out this mistake.
You have created a declaration for the constructor of the Function class without including it in your implementation (cpp file).
#include "Function.h"
Function::Function(){
// construction stuff here
}
int Function::help() //Error here
{
using namespace std;
cout << "Help";
return 1;
}
In the first Function.h file you have declared the constructor but not defined it. In the second Function.h file (the one that works) you have defined and declared the Function constructor. You can either define and declare in the header or file, or declare in the header file and define in the Function.cpp file.
For example, declare in the header file "Function.h":
class Function
{
Function();
}
and define here in "Function.cpp":
Function::Function(){}
Or the alternative is to declare and define in the header file "Function.h":
Class Function
{
Function(){}
}
The other thing that you have done in the second version of the header file is to initialise the member variable "status" in the "member initialisation list" which is a good thing to do (See Effective C++ by Scott Meyers, Item 4). Hope this helps :)