c++ constructor

class  {
public:
    Foo(int a) : data_(a) {}

    
    Foo(const Foo& other) {
        data_ = other.data_;
    }
    // copy assignment ctor
    Foo& operator=(const Foo& rhs) {
        if (*this != rhs) {
            data_ = rhs.data_;
        }
        return *this;
    }
    ~Foo();
private:
    int data_;
};