/** Numeric interval */
class Interval {

  private double base;  // low end
  private double width; // interval width
 
  /** Constructor: An Interval has base b and width w */
  public Interval(double b, double w) {
    base= b;
    width= w;
  }
  
  /** Constructor: An Interval with base 0 and width w */
  public Interval(double w) { this(0,w); }
  
  /** Constructor: An Interval with initial values given by declarations */
  public Interval() {}
  
  /** =Get left end of interval */
  public double getBase() { return base; }
  
  /** =Get right end of interval */
  public double getEnd() { return base + width; }

  /** Set left end of interval to base */
  public void setBase(double base) { 
    this.base= base;
  }
  
  /** Set width of interval to w */
  public void setWidth(double w) { width = w; }

}