c++ 11 copy assignment

class rule_of_five
{
    char * cstring; // raw pointer used as a handle to a dynamically-allocated memory block
public:
    rule_of_five( const char * arg )
        : cstring( new char[ std::strlen( arg ) + 1 ] ) // allocate
    {
        std::strcpy( cstring, arg ); // populate
    }
    ~rule_of_five()
    {
        delete[] cstring; // deallocate
    }
    rule_of_five( const rule_of_five & other ) // copy constructor
    {
        cstring = new char[ std::strlen( other.cstring ) + 1 ];
        std::strcpy( cstring, other.cstring );
    }
    rule_of_five( rule_of_five && other )
        : cstring( other.cstring ) // move constructor
    {
        other.cstring = nullptr;
    }
    rule_of_five & operator =( const rule_of_five & other ) // copy assignment
    {
        char * tmp_cstring = new char[ std::strlen( other.cstring ) + 1 ]; //chodzi mi o tmp_cstring
        std::strcpy( tmp_cstring, other.cstring );
        delete[] cstring;
        cstring = tmp_cstring;
       
        //zastanawiam się czy nie powinno być tutaj
        // delete[] tmp_cstring; bo przeciez wskaznik utworzony dynamicznie ale chyba jak to zrobię to usunę też co znajduje się w this->cstring
        return * this;
    }
    rule_of_five & operator =( rule_of_five && other ) // move assignment
    {
        if( this != & other ) // prevent self-move
        {
            delete[] cstring;
            cstring = other.cstring;
            other.cstring = nullptr;
        }
        return * this;
    }
    // alternatively, replace both assignment operators with
    //  rule_of_five& operator=(rule_of_five other)
    //  {
    //      std::swap(cstring, other.cstring);
    //      return *this;
    //  }
};