7. Rules for implicit default constructors

• You lose the implicit default constructor, if:

  1. you add a constructor taking no arguments:

     
         class Point {
         public:
             Point();
         };
     
     

  2. you add a constructor with all default arguments:

     
         class Point {
         public:
             Point( int x = 0, int y = 0 );
         };
     
     

  3. you add a constructor taking one or more arguments:

     
         class Point {
         public:
             Point( Point const* other );
         };
     
         int main()
         {
             Point pt; // ERROR: no default constructor!
             return 0;
         };