trouble with signals and slots

[Santosh Reddy]

QObject::connect(setbutton,SIGNAL(clicked()),num,SLOT(set(int nn, int nd)));

QObject::connect(setbutton,SIGNAL(clicked()),num,SLOT(set(int nn, int nd)));

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This is not legal in Qt. The slot should have less than or equal number of arguments as signal.

Fraction add(const Fraction& other);
Fraction subtract(const Fraction& other);
Fraction multiply(const Fraction& other);
Fraction divide(const Fraction& other);

Fraction add(const Fraction& other);
Fraction subtract(const Fraction& other);
Fraction multiply(const Fraction& other);
Fraction divide(const Fraction& other);

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All these function declaration are not possible int Qt, because Fraction is derived QObject, instead use somthing like

void add(const Fraction& other);
void subtract(const Fraction& other);
void multiply(const Fraction& other);
void divide(const Fraction& other);

void add(const Fraction& other);
void subtract(const Fraction& other);
void multiply(const Fraction& other);
void divide(const Fraction& other);

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Also typically all QObject derived class objects follow parent-child relationships, i.e the parent is passed during QObject construction. The best way to define Fraction class would be to (If you have decided to make it QObject)

class Fraction: public QObject {
Q_OBJECT
public:
    Fraction(int nn, int nd, QObject * parent = 0);
}

class Fraction: public QObject {
Q_OBJECT
public:
    Fraction(int nn, int nd, QObject * parent = 0);
}

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