class Foo
{ 
  public:
    Foo( int bar)=0;
    Foo( int bar = 777 );
    Foo( const Foo & ) = delete;
    Foo( int boo ) =default;
    Foo( unsigned int ) =default;
    Foo( unsigned int boo=999 );
    Foo &operator= ( const Foo & ) = delete;
    ~Foo();
};