## Interval

### Definition

The concept Interval describes the requirements for the template argument Interval of a Interval_skip_list<Interval>.

The concept does not specify, whether the interval is open or closed. It is up to the implementer of a model for this concept to define that.

### Creation

Interval in;
| default constructor.

### Types

Interval::Value
| The type of the lower and upper bound of the interval.

### Access Functions

Value | in.inf () | returns the lower bound.
Value | in.sup () | returns the upper bound.
bool | in.contains ( Value v)
|  | returns true, iff in contains v.
bool | in.contains_interval ( Value i, Value s)
|  | returns true, iff in contains (i,s).
bool | in == I | Equality test.
bool | in != I | Unequality test.

### Has Models

CGAL::Interval_skip_list_interval<Value>
CGAL::Face_interval

### See Also

Interval_skip_list