Double jagged array

It depends what you mean by 'dynamic'.

In C#, once you create an array, it's size cannot be changed. Methods such as Array.Resize actually create a new array of the required size and copy the elements of the old array to it.

A 'jagged array' is essentially an array of arrays and, unlike a rectangular array, the size of the constituent arrays need not be the same. However, once they've been created, the size of the constituent arrays cannot be changed.

For example:

  double[][] array = new double[2][];

creates a jagged array with 2 array elements.

  Each of those array elements can now be individually set:

  array[0] = new double[2];
  array[1] = new double[3];

They can also be changed to different arrays, including at runtime:

  int i = 4;
  array[0] = new double[i];

but there's no way in which the current array assigned to array[0] can have its size changed.

If you want something that can dynamically change its size as new elements are added, then use a List> rather than a jagged array of doubles.