how can we increase the length of array on runtime?

hello guys
how r u all ?

Q: How can we increase the length of array on runtime in c sharp?

i am trying this code:

public class TestArray

{

static int size = 0;

static int[] array = new int[size];

public TestArray()

{

size++;

Console.WriteLine(array[size]);

}

}

public class Program
{
public static void Main(string[] args)
{
TestArray t = new TestArray();
}
}

Reply soon

Thanks.

Well, you can use the Array.Resize method to increase the size of an array, as below:

using System;

public class TestArray

{

static int size = 0;

static int[] array = new int[size];

public TestArray()

{

Array.Resize(ref array, ++size);

Console.WriteLine(array.Length);

}

public class Program

{

public static void Main(string[] args)

{

TestArray t = new TestArray();

}

Notice though that this doesn't actually increase the size of the current Array object which cannot be changed once it's been created. Instead, it creates a new Array object and copies over the values of the elements of the old Array to the new one.

This isn't a particularly efficient process, particularly when you're only increasing the size by one.

A better idea is to use a List which starts off with a size of 4 and then, as new elements are added, doubles the size as required to accomodate them. If you haven't yet covered generic types in your studies, then you can use an ArrayList instead which works in a similar fashion but stores everything internally as type object using a process known as 'boxing' in the case of value types such as int. You therefore have to cast back to an int when you want to recover a particular element.

2 Replies

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Vulpes15y ago
Accepted answer
Well, you can use the Array.Resize method to increase the size of an array, as below:

using System;

public class TestArray
{
static int size = 0;
static int[] array = new int[size];
public TestArray()
{
Array.Resize(ref array, ++size);
Console.WriteLine(array.Length);
}
}

public class Program
{
public static void Main(string[] args)
{
TestArray t = new TestArray();
}
}

Notice though that this doesn't actually increase the size of the current Array object which cannot be changed once it's been created. Instead, it creates a new Array object and copies over the values of the elements of the old Array to the new one.

This isn't a particularly efficient process, particularly when you're only increasing the size by one.

A better idea is to use a List which starts off with a size of 4 and then, as new elements are added, doubles the size as required to accomodate them. If you haven't yet covered generic types in your studies, then you can use an ArrayList instead which works in a similar fashion but stores everything internally as type object using a process known as 'boxing' in the case of value types such as int. You therefore have to cast back to an int when you want to recover a particular element.
Faisal Ansari15y ago
Thanks Vulpes....

i got my answer

thanks again :)