Inserting new elements into the middle of an array...

[A$$Bandit]

I have an array, and for every element beginning with "[@]" I need to stick another empty element after it. How could I do this?

[hellswraith]

There probably is easier ways, but here is something I whipped up for you.

private void button1_Click(object sender, System.EventArgs e)
{
	string[] x;
	string[] y;
	int counter;
	int interiorCounter;

	counter = 0;
	interiorCounter = 0;

	// X is our original array.
	x = new string[5];
	x[0] = "hello";
	x[1] = "@";
	x[2] = "something";
	x[3] = "@";
	x[4] = "@";

	// We need to find out how many elements we are going to be adding.
	for (int i = 0; i <= x.GetUpperBound(0); i++)
	{
		if (x[i] == "@")
			counter++;
	}

	// Now we know how many to add, we need to add the x
	// array amount to the counter variable for the total.
	counter += x.GetUpperBound(0) + 1;

	// Now instantiate our new array.
	y = new string[counter];

	// Start filling the new array.
	for (int i = 0; i <= x.GetUpperBound(0); i++)
	{
		if(x[i] == "@")
		{
			y[interiorCounter] = "@";
			interiorCounter++;
			y[interiorCounter] = "your newly added element";
		}
		else
		{
			y[interiorCounter] = x[i];
		}
                
		interiorCounter++;	
	}

	// Show your newly added stuff....
	for(int i = 0; i <= y.GetUpperBound(0); i++)
	{
		MessageBox.Show(y[i].ToString());
	}
}

[Jeremy Martin]

I probably would use and array list. Here is an example out of the documentation.

using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList using Insert instead of Add.
      ArrayList myAL = new ArrayList();
      myAL.Insert( 0, "The" );
      myAL.Insert( 1, "fox" );
      myAL.Insert( 2, "jumped" );
      myAL.Insert( 3, "over" );
      myAL.Insert( 4, "the" );
      myAL.Insert( 5, "dog" );

      // Creates and initializes a new Queue.
      Queue myQueue = new Queue();
      myQueue.Enqueue( "quick" );
      myQueue.Enqueue( "brown" );

      // Displays the ArrayList and the Queue.
      Console.WriteLine( "The ArrayList initially contains the following:" );
      PrintValues( myAL );
      Console.WriteLine( "The Queue initially contains the following:" );
      PrintValues( myQueue );

      // Copies the Queue elements to the ArrayList at index 1.
      myAL.InsertRange( 1, myQueue );

      // Displays the ArrayList.
      Console.WriteLine( "After adding the Queue, the ArrayList now contains:" );
      PrintValues( myAL );

      // Search for "dog" and add "lazy" before it.
      myAL.Insert( myAL.IndexOf( "dog" ), "lazy" );

      // Displays the ArrayList.
      Console.WriteLine( "After adding \"lazy\", the ArrayList now contains:" );
      PrintValues( myAL );

      // Add "!!!" at the end.
      myAL.Insert( myAL.Count, "!!!" );

      // Displays the ArrayList.
      Console.WriteLine( "After adding \"!!!\", the ArrayList now contains:" );
      PrintValues( myAL );

      // Inserting an element beyond Count throws an exception.
      try  {
         myAL.Insert( myAL.Count+1, "anystring" );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());
      }
   }

   public static void PrintValues( IEnumerable myList )  {
      System.Collections.IEnumerator myEnumerator = myList.GetEnumerator();
      while ( myEnumerator.MoveNext() )
         Console.Write( "\t{0}", myEnumerator.Current );
      Console.WriteLine();
   }
}
/* 
This code produces the following output.

The ArrayList initially contains the following:
        The     fox     jumped  over    the     dog
The Queue initially contains the following:
        quick   brown
After adding the Queue, the ArrayList now contains:
        The     quick   brown   fox     jumped  over    the     dog
After adding "lazy", the ArrayList now contains:
        The     quick   brown   fox     jumped  over    the     lazy    dog
After adding "!!!", the ArrayList now contains:
        The     quick   brown   fox     jumped  over    the     lazy    dog     !!!
Exception: System.ArgumentOutOfRangeException: Insertion index was out of range.  Must be non-negative and less than or equal to size.
Parameter name: index
   at System.Collections.ArrayList.Insert(Int32 index, Object value)
   at SamplesArrayList.Main()
*/ 

Jeremy