JAGGED ARRAY

JAGGED ARRAY:
A jagged array is really an array of arrays. Each entry in the array is another array that can hold any number of items. Because each entry can hold any number of other items, the array has a jagged appearance. A Jagged Array is an array of an array in which the length of each array index can differ.
The following is a declaration of a single-dimensional array that has three elements, each of which is a single-dimensional array of integers:

int[][] testJaggedArray = new int[3][];

Before you can use testJaggedArray, its elements must be initialized. You can initialize the elements like this example:

testJaggedArray[0] = new int[5];
testJaggedArray[1] = new int[4];
testJaggedArray[2] = new int[2];

Each of the elements is a single-dimensional array of integers. The first element is an array of 5 integers, the second is an array of 4 integers, and the third is an array of 2 integers.
It is also possible to use initializers to fill the array elements with values, in which case you don't need the array size, for example:

testJaggedArray[0] = new int[] {1,3,5,7,9};
testJaggedArray[1] = new int[] {0,2,4,6};
testJaggedArray[2] = new int[] {11,22};

You can also initialize the array upon declaration like this:
int[][] testJaggedArray = new int [][]
{
new int[] {1,3,5,7,9},
new int[] {0,2,4,6},
new int[] {11,22}
};

You can use the following shortcut (notice that you cannot omit the new operator from the elements initialization because there is no default initialization for the elements):
int[][] testJaggedArray = {
new int[] {1,3,5,7,9},
new int[] {0,2,4,6},
new int[] {11,22}
};
You can access individual array elements like these examples:
// Assign 33 to the second element of the first array:
testJaggedArray[0][1] = 33;
// Assign 44 to the second element of the third array:
testJaggedArray[2][1] = 44;
It is possible to mix jagged and multidimensional arrays. The following is a declaration and initialization of a single-dimensional jagged array that contains two-dimensional array elements of different sizes:
int[][,] testJaggedArray = new int [3][,]
{
new int[,] { {1,3}, {5,7} },
new int[,] { {0,2}, {4,6}, {8,10} },
new int[,] { {11,22}, {99,88}, {0,9} }
};
You can access individual elements like this example, which displays the value of the element [1,0] of the first array (value 5):
Console.Write("{0}", testJaggedArray[0][1,0]);
Example
This example builds an array, testArray, whose elements are arrays. Each one of the array elements has a different size.
// cs_array_of_arrays.cs
using System;
public class TestArray
{
public static void Main()
{
// Declare the array of two elements:
int[][] testArray = new int[2][];

// Initialize the elements:
testArray[0] = new int[5] {1,3,5,7,9};
testArray[1] = new int[4] {2,4,6,8};

// Display the array elements:
for (int i=0; i < testArray.Length; i++)
{
Console.Write("Element({0}): ", i);

for (int j = 0 ; j < testArray[i].Length ; j++)
Console.Write("{0}{1}", testArray[i][j],
j == (testArray[i].Length-1) ? "" : " ");

Console.WriteLine();
}
}
}
Output
Element(0): 1 3 5 7 9
Element(1): 2 4 6 8