CODEWITHSUNDEEP
c++overloadingcopy-constructorassignment-operator
Sunny
Sunny

Reputation: 15

Error messages: with Copy constructor and Overloaded assignment operator

This is a question earlier asked by me. I'm getting compilation errors using the copy constructor suggested by the forum. 

class A
{
private:
    int a;
    int b;


public:

    A() { a = 0; b = 0; }
    int getA() { return a; }
    int getB() { return b; }
    A(const Beta& b) :a{ *b.X() }, b{ *b.Y } {} 

};

class Beta
{
private:
    int *x;
    int *y;

public:
    Beta(int a, int b) { x =&a; y = &b; }
    int* X() { return x; }
    int* Y() { return y; }

};

int main()
{
    B aObject;
    Alpha a1 = aBObject;
    Alpha a2;
    a2 = aBObject;

    return 0;

}

Without const Alpha(Beta& be) in the copy constructor argument

Error   C2061   syntax error: identifier 'Beta' 
Error   C2228   left of '.getY' must have class/struct/union 
Error   C2228   left of '.getX' must have class/struct/union 
Error   C2679   binary '=': no operator found which takes a right-hand operand of type 'Beta' (or there is no acceptable conversion)
Error   C2440   'initializing': cannot convert from 'Beta' to 'Alpha' 
Error   C2065   'be': undeclared identifier 
Error   C2535   'Alpha::Alpha(void)': member function already defined or declared

With const Alpha(const Beta& be) in the copy constructor argument

Error (active)  the object has type qualifiers that are not compatible with the member function "Beta::getX" 
Error (active)  the object has type qualifiers that are not compatible with the member function "Beta::getY" 

Error   C2061   syntax error: identifier 'Beta' 
Error   C2228   left of '.getY' must have class/struct/union 
Error   C2228   left of '.getX' must have class/struct/union 
Error   C2679   binary '=': no operator found which takes a right-hand operand of type 'Beta' (or there is no acceptable conversion)
Error   C2440   'initializing': cannot convert from 'Beta' to 'Alpha' 
Error   C2065   'be': undeclared identifier 
Error   C2535   'Alpha::Alpha(void)': member function already defined or declared

Upvotes: 0

Views: 159

Answers (2)

john
john

Reputation: 87959

There are no copy constructors (or assignment operators) in your code. But anyway that's not the issue. They issue that your code for Alpha uses Beta before Beta has been defined. That's what the compiler is complaining about, it doesn't recognise Beta at the point you first use it.

Just move Beta so it's definition is before Alpha and everything will compile.

Upvotes: 0

NewMe
NewMe

Reputation: 162

Is this what you want?

class Beta
{
private:
    int *x;
    int *y;

public:
    Beta() { x = nullptr; y = nullptr; }
    int* getX() { return x; }
    int* getY() { return y; }

};

class Alpha
{
private:
    int a;
    int b;


public:

    Alpha() { a = 0; b = 0; }
    int getA() { return a; }
    int getB() { return b; }
    Alpha( Beta& be) :a{ *be.getX() }, b{ *be.getY() } {} 
//It is not copy Constructor. You can't pass const reference here because getX getY returns pointer. So it could break const contract

};



int main()
{
    Beta aBetaObject;
    Alpha a1 = aBetaObject;
    Alpha a2;
    a2 = aBetaObject;

    return 0;

}

Upvotes: 1

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