#include <string>
using std::string;
class Operand
{
public:
...
virtual void empty();
virtual void fill();
virtual Operand* mix(Operand* op2);
};
#include "operand.h"
#include <string>
using std::string;
//class Operand; Errore sia se non cè sia se c'è
class Barrel: public Operand
{
...
virtual void empty();
virtual void fill();
virtual Barrel* mix(Operand* op2);
protected:
double capacity, content, temperature;
};
#include "calculatorwindow.h"
#include "operand.h"
using std::string;
class CalculatorWindow;
class Barrel;
class Operand;
class Calculator
{
public:
...
Operand* operand1;
Operand* operand2;
double intoperand;
string operation;
string print;
bool continue;
...
void Fill(CalculatorWindow * calc);
void Empty(CalculatorWindow * calc);
Operand* Mix(CalculatorWindow * calc);
};
"Invalid use of incomplete type struct Operand forward declaration of struct Operand"...