[Solved] Will these implementations cause memory leakage?

by


The 1st alternative will cause a memory leak whether you pass true or false to the constructor of Derived. Exactly one Structure will be allocated on the heap, which is then copied by the default copy constructor of Structure when the assignment 

 var = structure;

is executed.

If you:

  • replace the internal var variable type by a pointer as suggested in the question
  • delete the pointer in the destructor
  • implement a copy constructor for Base taking care of duplicating var by a new allocation

you should not have any problem. 

struct Structure {
    int a;
    int b;
    Structure() { a=1; b=2; }
    Structure(int num1, int num2) : a(num1), b(num2){}
};

class Base {
    private:
        Structure *var;
    public: 
    Base(Structure *structure) {
        var = structure;
    }
    Base(const Base &b) {
        var = new Structure(*b.var);
    }
    virtual ~Base(){
        delete var;
        var = 0;
    }
};

solved Will these implementations cause memory leakage?