CODEWITHSUNDEEP
c++initialization
sassy_rog
sassy_rog

Reputation: 1097

Equate stack object to another inside an object C++

I have two object, call the A and B e.g

class A {
   private:
     int x; 
     int y;

   public:
     A();
     A(int x, int y);
     void setX(int);
     void setY(int);
};

class B {
   private:
     const A a1;

   public:
     B();
     B(int x, int y) {
       //my problem is here
       A a(x, y);
       this->a1 = a;
     };
};

If B is initialised with parameters, I want to have a1 initialised with parameters as well which B is initialised with, hence A(int x, int y).

I don't want a1 initialised in heap.

I currently getting this error

no operator "=" matches these operands -- operand types are: const Brain = Brain

Amend

From the answer below by @songyuanyao

B::B(int x, int y) : a1(x, y){};

it works but I have a different problem now due to my lack of knowledge for const. When I call setX and setY from A(int x, int y) like this

A::A(int x, int y) {
    setX(x);
    setY(y);
}

void A::setX(int x) {
    this->x = x;
}

void A::setY(int y) {
    this->y = y;
}

it doesn't seem to change the x and y values/attributes of class A.

Upvotes: 1

Views: 36

Answers (1)

songyuanyao
songyuanyao

Reputation: 172924

You should initialize the const data member with member initializer list. As const object, it could be initialized, but can't be assigned; so this->a1 = a; doesn't work.

For members that cannot be default-initialized, such as members of reference and const-qualified types, member initializers must be specified.

e.g.

B(int x, int y) : a1(x, y) {}

Upvotes: 3

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