Code:
using System;
using System.Collections;
class GrowableArray : IEnumerable
{
object[] a;
public GrowableArray(int size)
{
a = new object[size];
}
public GrowableArray() : this(8) {}
void Grow()
{
object[] b = new object[2 * a.Length];
Array.Copy(a, b, a.Length);
a = b;
}
public object this[int i]
{
set
{
if (i >= a.Length) Grow();
a[i] = value;
}
get
{
if (i >= a.Length) Grow();
return a[i];
}
}
public IEnumerator GetEnumerator()
{
return new GAEnumerator(a);
}
class GAEnumerator : IEnumerator
{
object[] a;
int i = -1;
public GAEnumerator(object[] a) { this.a = a; }
public object Current
{
get
{
return a[i];
}
}
public void Reset()
{
i = -1;
}
public bool MoveNext()
{
do i++;
while (i < a.Length && a[i] == null);
if (i == a.Length)
return false;
else return true;
}
}
}
class Test
{
public static void Main()
{
GrowableArray a = new GrowableArray(2);
a[0] = 0;
a[1] = 1;
a[3] = 3;
foreach (object x in a) Console.Write(" " + x);
}
Output:
Demonstrating foreach Interface by Displaying Numbers from 100 to 105 :
100
101
102
103
104
105
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