CODEWITHSUNDEEP
c++
dromodel
dromodel

Reputation: 10243

Is it possible to call default constructor from move constructor?

I'm implementing a move constructor and need to initialize other back to it's original state, as implemented in the default constructor. Is this possible or do I need to duplicate the code?

class Class
{
  Class() { /* code to duplicate */ }
  Class(Class&& other) :
    mMember(other.mMember) {
    other.Class(); // code to duplicate?
  }
};

I know other.Class() is invalid here and I know that constructors can call each other with C++11 now.

Upvotes: 2

Views: 375

Answers (1)

Guillaume Racicot
Guillaume Racicot

Reputation: 41820

The best way would be to reassign it. Since the object is already constructed, it would be a mistake to call the constructor again.

However, you can create an instance and call the assignement operator:

Class(Class&& other) noexcept : mMember(std::move(other.mMember)) {
    other = Class{};
}

Another way would be to default construct your class and swap values with the old one:

Class(Class&& other) noexcept {
    std::swap(mMember, other.mMember);
}

If you really need other to take the value it would from calling the default constructor, you can do this:

Class(Class&& other) noexcept : Class() {
    std::swap(mMember, other.mMember);
}

It will call the default constructor in the new object and then swap the values from the other object.

Upvotes: 4

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