Pointer to Incomplete Class Type Is Not Allowed
For Some Reason I Cannot Use Functions Attached to the Object I Want to Use. I Added a Comment to the Line That Is Not Working. as an Error I Get "Error...
For some reason I cannot use functions attached to the object I want to use. I added a comment to the line that is not working. As an error I get "Error; pointer to incomplete class type is not allowed" Please help
This is code in dokter.ccp
int counter = 0;
for (list<Wielrenner*>::iterator it = wielrenners.begin(); it != wielrenners.end(); it++){
Wielrenner* wielrennerOB = *it;
cout << "\nID: " << counter;
cout << "List size: " << persons.size() << endl;
wielrennerOB->print(); // This is not working
counter++;
}
This is code in wielrenner.h
#ifndef WIELRENNER_H_
#define WIELRENNER_H_
//#include <fstream>
#include "persoon.h"
#include "Onderzoek.h"
class Wielrenner :
public Persoon
{
public:
Wielrenner(string, string, Adres, string, Datum, Datum, string, int, float, float, float,list<Onderzoek>* );
~Wielrenner(void);
int getLengte() const;
float getGewicht() const;
float getVo2max() const;
float getMaxVermogen() const;
list<Onderzoek> getOnderzoekenList();
void setLengte(int);
void setGewicht(float);
void setVo2max(float);
void setMaxVermogen(float);
void voegOnderzoekToeList(Onderzoek);
void showOnderzoeksList();
void setOnderzoeksLijst(list<Onderzoek>&);
void print();
void printFile(ofstream&);
private:
int lengte;
float gewicht;
float vo2max;
float maxVermogen;
list<Onderzoek> onderzoeken;
};
#endif /* WIELRENNER_H_ */
code in wielrenner.CCP
using namespace std;
#include <string>
#include "Wielrenner.h"
/*
#include "Onderzoek.h"
*/
Wielrenner::Wielrenner(string voornaam, string achternaam, Adres adres, string telefoon, Datum datumInDienst, Datum geboorteDatum,
string persoonType, int lengte, float gewicht, float vo2max, float maxVermogen,list<Onderzoek>* onderzoeken)
: lengte(lengte),
gewicht(gewicht),
vo2max(vo2max),
maxVermogen(maxVermogen),
Persoon(voornaam, achternaam, adres, telefoon, datumInDienst, geboorteDatum, persoonType)
{
}
Wielrenner::~Wielrenner(void)
{
}
//setten van gegevens
void Wielrenner::setLengte(int newLengte){
lengte = newLengte;
}
void Wielrenner::setGewicht(float newGewicht){
gewicht = newGewicht;
}
void Wielrenner::setVo2max(float newVo2max){
vo2max = newVo2max;
}
void Wielrenner::setMaxVermogen(float newMaxVermogen){
maxVermogen = newMaxVermogen;
}
void Wielrenner::voegOnderzoekToeList(Onderzoek newOnderzoek){
onderzoeken.push_back(newOnderzoek);
}
void Wielrenner::showOnderzoeksList(){
int teller=0;
for (list<Onderzoek>::iterator it = onderzoeken.begin(); it != onderzoeken.end(); it++){
Onderzoek onderzoekOB = *it;
cout << teller << " - ";
onderzoekOB.print();
teller++;
}
}
void Wielrenner::setOnderzoeksLijst(list<Onderzoek>& newOnderzoeksLijst){
onderzoeken = newOnderzoeksLijst;
}
void Wielrenner::print(){
cout << "(" << persoonID << ") Persoon: " << endl;
cout << persoonType << endl;
cout << voornaam << " " << achternaam << endl;
adres.print();
cout << telefoon << endl;
cout << "Datum in dienst: ";
datumInDienst.print();
cout << "Geboortedatum: ";
geboorteDatum.print();
cout << "> Extra wielrenner gegevens: " << endl;
cout << "Lengte: " << lengte << endl;
cout << "Gewicht: " << gewicht << endl;
cout << "vo2max: " << vo2max << endl;
cout << "maxVermogen: " << maxVermogen << endl;
}
void Wielrenner::printFile(ofstream &myfile){
myfile << persoonID << "\n";
myfile << persoonType << "\n";
myfile << voornaam << " " << achternaam << "\n";
adres.printFile(myfile);
myfile << telefoon << "\n";
datumInDienst.printFile(myfile);
geboorteDatum.printFile(myfile);
myfile << lengte << "\n";
myfile << gewicht << "\n";
myfile << vo2max << "\n";
myfile << maxVermogen << "\n";
}
// returnen van gegevens
int Wielrenner::getLengte() const{
return lengte;
}
float Wielrenner::getGewicht() const{
return gewicht;
}
float Wielrenner::getVo2max() const{
return vo2max;
}
float Wielrenner::getMaxVermogen() const{
return maxVermogen;
}
list<Onderzoek> Wielrenner::getOnderzoekenList(){
return onderzoeken;
}
6 Answers
An "incomplete class" is one declared but not defined. E.g.
class Wielrenner;
as opposed to
class Wielrenner
{
/* class members */
};
You need to #include "wielrenner.h" in dokter.ccp
One thing to check for...
If your class is defined as a typedef:
typedef struct myclass { };
Then you try to refer to it as struct myclass anywhere else, you'll get Incomplete Type errors left and right. It's sometimes a mistake to forget the class/struct was typedef'ed. If that's the case, remove "struct" from:
typedef struct mystruct {}...
struct mystruct *myvar = value;
Instead use...
mystruct *myvar = value;
Common mistake.
You get this error when declaring a forward reference inside the wrong namespace thus declaring a new type without defining it. For example:
namespace X
{
namespace Y
{
class A;
void func(A* a) { ... } // incomplete type here!
}
}
...but, in class A was defined like this:
namespace X
{
class A { ... };
}
Thus, A was defined as X::A, but I was using it as X::Y::A.
The fix obviously is to move the forward reference to its proper place like so:
namespace X
{
class A;
namespace Y
{
void func(X::A* a) { ... } // Now accurately referencing the class`enter code here`
}
}
I came accross the same problem and solved it by checking my #includes. If you use QKeyEvent you have to make sure that you also include it.
I had a class like this and my error appeared when working with "event"in the .cpp file.
myfile.h
#include <QKeyEvent> // adding this import solved the problem.
class MyClass : public QWidget
{
Q_OBJECT
public:
MyClass(QWidget* parent = 0);
virtual ~QmitkHelpOverlay();
protected:
virtual void keyPressEvent(QKeyEvent* event);
};
The problem also occurs when header files are not included explicitly where they are needed, but implicitly through other heading files.
Check out if you are missing some import.
James Sterling reports on renewable energy developments, climate policy, ecological conservation, and green tech innovations around the globe.
