Arrays in C#

1. What are the 3 different types of arrays that we have in C#?
• Single Dimensional Arrays
• Multi Dimensional Arrays also called as rectangular arrays
• Array Of Arrays also called as jagged arrays

using System;

class Program

{

    static void Main()

    {

        // Declare local jagged array with 3 rows.

        int[][] jagged = new int[3][];

        // Create a new array in the jagged array, and assign it.

        jagged[0] = new int[2];

        jagged[0][0] = 1;

        jagged[0][1] = 2;

        // Set second row, initialized to zero.

        jagged[1] = new int[1];

        // Set third row, using array initializer.

        jagged[2] = new int[3] { 3, 4, 5 };

        // Print out all elements in the jagged array.

        for (int i = 0; i < jagged.Length; i++)

        {

            int[] innerArray = jagged[i];

            for (int a = 0; a < innerArray.Length; a++)

            {

               Console.Write(innerArray[a] + " ");

            }

            Console.WriteLine();

        }

    }

}

Output

"1 2"

"0"

"3 4 5"

Description. It declares a jagged array. The word 'jagged' doesn't even exist in the C# language, meaning that you don't need to use this word in your code. Jagged is just a descriptive variable name I use.
Initializations used. It initializes some values in the jagged array. There are lots of square brackets. This is very different from a 2D array, which uses commas instead of pure brackets.
Assigning jagged arrays. It assigns an array at the second index. Above you should see that indexes in the array are assigned to new int[] arrays. This is because the jagged array only allocates the list of empty references to arrays at first. You have to make your own arrays to put in it. We see the array initializer syntax here, which is less verbose than some other ways.
Looping over jagged arrays. You will want to examine each item in the jagged array. We must call Length first on the array of references, and then again on each inner array. The Console calls above are just for the example.

What is the difference between arrays in C# and arrays in other programming languages?
Arrays in C# work similarly to how arrays work in most other popular languages There are, however, a few differences as listed below

1. When declaring an array in C#, the square brackets ([]) must come after the type, not the identifier. Placing the brackets after the identifier is not legal syntax in C#.
int[] IntegerArray; // not int IntegerArray[];

2. Another difference is that the size of the array is not part of its type as it is in the C language. This allows you to declare an array and assign any array of int objects to it, regardless of the array's length.

int[] IntegerArray; // declare IntegerArray as an int array of any size
IntegerArray = new int[10]; // IntegerArray is a 10 element array
IntegerArray = new int[50]; // now IntegerArray is a 50 element array


Are arrays in C# value types or reference types?
Reference types.

What is the base class for all arrays in C#?
System.Array

How do you sort an array in C#?
The Sort static method of the Array class can be used to sort array items.

Give an example to print the numbers in the array in descending order?
using System;
namespace ConsoleApplication
{
class Program
{
static void Main()
{
int[] Numbers = { 2, 5, 3, 1, 4 };
//Print the numbers in the array without sorting
Console.WriteLine("Printing the numbers in the array without sorting");
foreach (int i in Numbers)
{
Console.WriteLine(i);
}
//Sort and then print the numbers in the array
Console.WriteLine("Printing the numbers in the array after sorting");
Array.Sort(Numbers);
foreach (int i in Numbers)
{
Console.WriteLine(i);
}
//Print the numbers in the array in descending order
Console.WriteLine("Printing the numbers in the array in descending order");
Array.Reverse(Numbers);
foreach (int i in Numbers)
{
Console.WriteLine(i);
}
}
}
}

What property of an array object can be used to get the total number of elements in an array?
Length property of array object gives you the total number of elements in an array. An example is shown below.
using System;
namespace ConsoleApplication
{
class Program
{
static void Main()
{
int[] Numbers = { 2, 5, 3, 1, 4 };
Console.WriteLine("Total number of elements = " +Numbers.Length);
}
}
}

Give an example to show how to copy one array into another array?
We can use CopyTo() method to copy one array into another array. An example is shown below.
using System;
namespace ConsoleApplication
{
class Program
{
static void Main()
{
int[] Numbers = { 2, 5, 3, 1, 4 };
int[] CopyOfNumbers=new int[5];
Numbers.CopyTo(CopyOfNumbers,0);
foreach (int i in CopyOfNumbers)
{
Console.WriteLine(i);
}
}
}
}

Can you use foreach iteration on arrays in C#?
Yes, since array type implements IEnumerable, you can use foreach iteration on all arrays in C#.