In Looping cann't remove and insert ArrayList?

moe sat

I am a C# beginner.I've some problem with this exercise.Can you give me some advise?Because I've no ide what should i do.

ArrayList arrayList = new ArrayList();
Console.Write("Enter code:");
arrayList.Add(Console.ReadLine());
Console.Write("Enter qty:");
arrayList.Add(Convert.ToInt32(Console.ReadLine()));
Console.Write("Enter code:");
arrayList.Add(Console.ReadLine());
Console.Write("Enter qty:");
arrayList.Add(Convert.ToInt32(Console.ReadLine()));

ArrayList looplist = new ArrayList(arrayList);

foreach (object text in looplist)
{
if (Convert.ToString(text) == "p")
{
arrayList.RemoveAt(0);
arrayList.Insert(0, "Programming");
}
else
{
arrayList.RemoveAt(2);
arrayList.Insert(2, "Graphic");
}

Console.WriteLine("{0}", text);
}

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes13y ago
It is in fact working because if I run this and enter p 5 g 5 as you've done:

using System;
using System.Collections;

class Test
{
static void Main()
{
ArrayList arrayList = new ArrayList();
Console.Write("Enter code:");
arrayList.Add(Console.ReadLine());
Console.Write("Enter qty:");
arrayList.Add(Convert.ToInt32(Console.ReadLine()));
Console.Write("Enter code:");
arrayList.Add(Console.ReadLine());
Console.Write("Enter qty:");
arrayList.Add(Convert.ToInt32(Console.ReadLine()));

ArrayList looplist = new ArrayList(arrayList);

foreach (object text in looplist)
{
if (Convert.ToString(text) == "p")
{
arrayList.RemoveAt(0);
arrayList.Insert(0, "Programming");
}
else
{
arrayList.RemoveAt(2);
arrayList.Insert(2, "Graphic");
}

Console.WriteLine("{0}", text);
}

Console.WriteLine("\nlooplist till contains\n");
foreach(object o in looplist) Console.WriteLine(o);
Console.WriteLine("\nBut arrayList now contains\n");
foreach(object o in arrayList) Console.WriteLine(o);
Console.ReadKey();
}

}

The output is:

Enter code:p
Enter qty:5
Enter code:g
Enter qty:5
p
5
g
5

looplist till contains

p
5
g
5

But arrayList now contains

Programming
5
Graphic
5

So you've changed arrayList but not the copy you made from it, looplist.

0
moe sat13y ago
arrayList.Remove is not working and insert too.Why don't remove and insert?
my output is:
p
5
g
5
not change to "Programming" and Graphic??
0
Vulpes13y ago
I don't see the problem - it seems to be working fine.

Remember that it's arrayList you're changing, not the copy looplist.
0