Remove the iterator class from the listing and replace the call to the iterator class, inside the iteration sample(line 29), by using the yield operator of C#2.
The output of the Problem() method should remain the same.
1: using System;
2: using System.Collections;
3:
4: namespace Puzzles
5: {
6:
7: public class Enumarators
8: {
9: public static void Problem()
10: {
11: var myValues = new[] { "a", "b", "c", "d" };
12: var col = new IterationSample(myValues);
13: foreach (var x in col)
14: {
15: Console.WriteLine(x);
16: }
17: }
18:
19: public class IterationSample : IEnumerable
20: {
21: internal object[] values;
22:
23: public IterationSample(object[] values)
24: {
25: this.values = values;
26: }
27: public IEnumerator GetEnumerator()
28: {
29: return new Iterator(this); //Change this line by using yield
30: }
31: }
32:
33: public class Iterator:IEnumerator
34: {
35: IterationSample parent;
36: int position;
37:
38: internal Iterator(IterationSample parent)
39: {
40: this.parent = parent;
41: position = -1;
42: }
43: public bool MoveNext()
44: {
45: if (position != parent.values.Length)
46: {
47: position++;
48: }
49: return position < parent.values.Length;
50: }
51: public object Current
52: {
53: get
54: {
55: if (position==-1 || position==parent.values.Length)
56: {
57: throw new InvalidOperationException();
58: }
59: return parent.values[position];
60: }
61: }
62: public void Reset()
63: {
64: position = -1;
65: }
66: }
67: }
68: }
69:
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