Interval(double floor_val, double ceil_val);
Interval(double floor_val, OPERATOR floor_op, double ceil_val, OPERATOR ceil_op);
virtual ~Interval();
+ Interval& set(double floor_val, double ceil_val);
+ Interval& set(double floor_val, OPERATOR floor_op, double ceil_val, OPERATOR ceil_op);
Interval& operator <(double value);
Interval& operator <=(double value);
Interval& operator >(double value);