cppreference.com > C/C++ Keywords > enum enum Syntax:
      enum name {name-list} var-list;
The enum keyword is used to create an enumerated type named name that consists of the elements in name-list. The var-list argument is optional. Example code:
       enum color {red, orange, yellow, green, blue, indigo, violet};
       color c1 = indigo;
       if( c1 == indigo ) {
         cout << "c1 is indigo" << endl;
       }