void InvocationCounter::def(State state, int init, Action action) {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(0 <= state && state < number_of_states, "illegal state");
      assert(0 <= init  && init  < count_limit, "initial value out of range");

  {- -------------------------------------------
  (1) フィールドの初期化
      (InvocationCounter クラスの static フィールドの初期化)
      ---------------------------------------- -}

      _init  [state] = init;
      _action[state] = action;
    }