Question

Example:

class C
{
  public:
    void operator =(int i) {}
};

class SubC : public C
{
};

The following gives compilation error:

SubC subC;
subC = 0;

“no match for ‘operator=’ in ‘subC = 0′”

Some sources state that it is because assignment operators are not inherited. But isn’t it simply because default constructed copy-assignment of SubC overshadows them?

Answer 1

The copy assignment operator is automatically generated in the derived class. This causes the base class’s assignment operator to be hidden due to the regular name hiding rules of C++. You can unhide the name in the base class through the “using” directive. For example:

class C
{
  public:
    void operator =(int i) {}
};

class SubC : public C
{
  public:
    using C::operator=;
};