| using System;
using System.Collections;
public struct Interval: IEnumerable{
private readonly int from, to;
public Interval(int from, int to){
this.from = from;
this.to = to;
}
public int From{
get {return from;}
}
public int To{
get {return to;}
}
public int Length{
get {return Math.Abs(to - from) + 1;}
}
public int this[int i]{
get {if (from <= to){
if (i >= 0 && i <= Math.Abs(from-to))
return from + i;
else throw new Exception("Error"); }
else if (from > to){
if (i >= 0 && i <= Math.Abs(from-to))
return from - i;
else throw new Exception("Error"); }
else throw new Exception("Should not happen"); }
}
// Overloaded operators have been hidden in this version
private class IntervalEnumerator: IEnumerator{
private readonly Interval interval;
private int idx;
public IntervalEnumerator (Interval i){
this.interval = i;
idx = -1; // position enumerator outside range
}
public Object Current{
get {return (interval.From < interval.To) ?
interval.From + idx :
interval.From - idx;}
}
public bool MoveNext (){
if ( idx < Math.Abs(interval.To - interval.From))
{idx++; return true;}
else
{return false;}
}
public void Reset(){
idx = -1;
}
}
public IEnumerator GetEnumerator (){
return new IntervalEnumerator(this);
}
} |