In the following example, a member initialization list appears in the inline definition of the constructor, inside the class body:

 class ratio {private: int x, y;public: ratio(int top, int bot) :x(top), y(bot){}};

If you prefer to define the constructor outside the class, you can still use a member initialization list. First, provide only a declaration (i.e., a prototype) inside the class body:

 class ratio {private: int x, y;public: ratio(int top, int bot); // no initialization list here};

Next, place the member-initialization list in the constructor