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Arrays in C#

7 min read

  • It’s a multi value in one variable with the same data type

  • هي عبارة عن Reference Types يعني لما بعمل array جديدة يبقا بعمل object from array class

  • Non-primitive → Reference → Heap

Array Properties

  1. Fixed Type (Same Data Type)
  2. Fixed Size (Static Array)
  3. Sequential in the memory
  4. Support direct accessing

Array Types

  1. Single Dimensional Array
  2. Multi Dimensional Array
  3. Jadgged Array

Create an Array

DataType[] arrayName = new DateType[size];
 
int[] Arr;
//Declaration for refrence of int Array 
//Zero Bytes have been allocated in Heap
 
Arr = new int[5]; // allocated in heap now : To use later
// Will give here initial value and in this case will be 0 (default)
// String -> NULL
 
int[] Arr = new int[5] { 3, 4, 5, 6, 7 };
 
int[] Arr = new int[] { 3, 4, 5, 6, 7 };
 
int[] Arr =  { 3, 4, 5, 6, 7 };

Access the elements and change it

طبعا بتوصل للعناصر من خلال ال index بتاعها

string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
Console.WriteLine(cars[0]);
// Outputs Volvo

وبرضو بنفس الطريقة أقدر أغير قيمة جواه

string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
cars[0] = "Opel";
Console.WriteLine(cars[0]);
// Now outputs Opel instead of Volvo

Loop through Array

ممكن أستخدم أي طريقة هنا Iteration Statements وخصوصا ال foreach

int[] arr = new int[3]; // 0 0 0
for(int i = 0; i < arr.Length; i++)
{
	arr[i] = int.Parse(Console.ReadLine());
}
 
// We can't use foreach in this case

Array as reference

int[] Arr01 = { 1, 7, 5, 3, 8, 6, 4, 2 };
int[] Arr02 = { 7, 8, 9 };
 
Console.WriteLine($"Arr01 {Arr01.GetHashCode()}"); // Arr01 27252167
Console.WriteLine($"Arr02 {Arr02.GetHashCode()}"); // Arr02 59941933
 
Arr02 = Arr01;
/// Same Object , Two References 
Console.WriteLine("Arr02 = Arr01");
 
Arr02 = (int[])Arr01.Clone();
/// int[] = (int[])object ;
/// Derived = Base : Not Valid must use Explicit Casting
/// ref To Base = Derived : Valid
/// Arr02 new Object with new(diff) identity but same state as Arr01
Console.WriteLine("After Clone");
Console.WriteLine($"Arr01 {Arr01.GetHashCode()}"); // Arr01 27252167
Console.WriteLine($"Arr02 {Arr02.GetHashCode()}"); // Arr02 2606490
 
 
for (int i = 0; i < Arr02.Length; i++)
    Console.Write($"{Arr02[i]} , ");
Console.WriteLine("");
/*
Arr01 27252167
Arr02 59941933
Arr02 = Arr01
After Clone
Arr01 27252167
Arr02 2606490
1 , 7 , 5 , 3 , 8 , 6 , 4 , 2 ,
*/
  • اللي حصل ان كل array متخزنة في الأول في ال heap عادي بس في اماكن مختلفة، ولو خليت الأول بيساوي التاني فدا معناه اني بس خليت الأول يشاور على التاني والداتا اللي كانت في الأول بقت unreachable زي ما قولنا قبل كدا
  • انما لو عايز أخزن الداتا في الarray التانية فكدا لازم أخد نسخة من المحتوى بتاعه الأول وأحطه في التاني
  • بس في الحالة دي مش هينفع لأن clone بترجع من النوع object ودا يعتبر الشامل ومن قواعد ال OOP ان ال base = derived انما ال derived != base فكدا لازم أعمل Explicit Casting
  • شرح قاعدة ال OPP: مش كل class هو car ولكن كل car عبارة عن class

Array Methods

Array Length

string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
Console.WriteLine(cars.Length);
// Outputs 4
 
int[] Arr01 = { 1, 7, 5, 3, 8, 6, 4, 2 };
Array.Sort(Arr01);
//rank: نوعها ايه
Console.WriteLine($"Size {Arr01.Length} , Number of Dimensions {Arr01.Rank}");

Array copy

Array.Copy method is used to copy elements from one array to another. This method provides a way to duplicate the contents of an array into another array, either partially or fully, depending on the parameters used.

Basic Syntax

public static void Copy(Array sourceArray, Array destinationArray, int length);

Parameters

  • sourceArray: The array that contains the data to be copied.
  • destinationArray: The array that will receive the copied data.
  • length: The number of elements to copy.

Overloads

There are several overloads of the Array.Copy method that allow for more flexibility:

  1. Basic Copy

    Array.Copy(sourceArray, destinationArray, length);

  2. Specifying Indices

    public static void Copy(Array sourceArray, int sourceIndex, Array destinationArray, int destinationIndex, int length);

    Copies length elements from sourceArray starting at sourceIndex to destinationArray starting at destinationIndex.

Example Usage

Here’s an example demonstrating how to use Array.Copy:

using System;
 
class Program
{
    static void Main()
    {
        int[] sourceArray = { 1, 2, 3, 4, 5 };
        int[] destinationArray = new int[5];
 
        // Copying the entire array
        Array.Copy(sourceArray, destinationArray, sourceArray.Length);
 
        // Displaying the contents of the destination array
        foreach (int item in destinationArray)
        {
            Console.WriteLine(item);
        }
 
        // Copying a part of the array
        int[] partialDestinationArray = new int[3];
        Array.Copy(sourceArray, 1, partialDestinationArray, 0, 3);
 
        // Displaying the contents of the partial destination array
        foreach (int item in partialDestinationArray)
        {
            Console.WriteLine(item);
        }
    }
}

Important Considerations

  • Type Compatibility: Both the source and destination arrays must be of compatible types, otherwise a runtime exception will occur.
  • Bounds Checking: Ensure that the destination array is large enough to hold the copied elements to avoid an ArgumentOutOfRangeException.
  • Shallow Copy: Array.Copy performs a shallow copy, meaning if the array contains reference types, only the references are copied, not the actual objects. Shallow Copy

Using Array.Copy is a straightforward way to duplicate or move data between arrays in C#, providing flexibility through its various overloads and ease of use.

We talked more about Cs Shallow and deep copy

Array Clone

دي بستخدمها عشان أعمل Deep Copy

Sort an Array

هنستخدم ال method اللي اسمها Sort() وبترتب تصاعدي وال method دي موجودة جوا class ال Array

// Sort a string
string[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
Array.Sort(cars);
foreach (string i in cars)
{
  Console.WriteLine(i);
}
 
// Sort an int
int[] myNumbers = {5, 1, 8, 9};
Array.Sort(myNumbers);
foreach (int i in myNumbers)
{
  Console.WriteLine(i);
}
  • We can reverse an array with Reverse function.
int[] arr = {10, 20, 30};
Array.Reverse(arr); // 30 , 20 , 10
  • If I want to sort desc: So we will use Sort by default asc, and then Reverse
int[] arr = {20, 100, 50, 10};
Array.Sort(arr); // 10, 20, 50, 100
Array.Reverse(arr); // 100, 50, 20, 10

System.Linq Namespace

بتخليني أعمل فيلتر على الداتا وأنا بشتغل على ال DB مثلًا Other useful array methods, such as Min, Max, and Sum, can be found in the System.Linq namespace

using System;
using System.Linq;
 
namespace MyApplication
{
  class Program
  {
    static void Main(string[] args)
    {
      int[] myNumbers = {5, 1, 8, 9};
      Console.WriteLine(myNumbers.Max());  
      // returns the largest value
      Console.WriteLine(myNumbers.Min());  
      // returns the smallest value
      Console.WriteLine(myNumbers.Sum());  
      // returns the sum of elements
    }
  }
}

Multidimensional Arrays

A multidimensional array is basically an array of arrays.

dataType[,] arrayName = new dataType[dimension1, dimension2];
// `dimension1`: The size of the first dimension. (X)
// `dimension2`: The size of the second dimension. (Y)
 
// OR
int[,] numbers = { {1, 4, 2}, {3, 6, 8} };

Good to know: The single comma [,] specifies that the array is two-dimensional. A three-dimensional array would have two commas: int[,,].

example

using System;
 
class Program
{
    static void Main()
    {
        // Create a 3x3 two-dimensional array
        int[,] matrix = new int[3, 3];
 
        // Initialize the array
        matrix[0, 0] = 1;
        matrix[0, 1] = 2;
        matrix[0, 2] = 3;
        matrix[1, 0] = 4;
        matrix[1, 1] = 5;
        matrix[1, 2] = 6;
        matrix[2, 0] = 7;
        matrix[2, 1] = 8;
        matrix[2, 2] = 9;
 
        // Display the array elements
        for (int i = 0; i < matrix.GetLength(0); i++)
        {
            for (int j = 0; j < matrix.GetLength(1); j++)
            {
                Console.Write(matrix[i, j] + "\t");
            }
            Console.WriteLine();
        }
    }
}
 
 
using System;
 
class Program
{
    static void Main()
    {
        // Create and initialize a 2x3 two-dimensional array
        int[,] matrix = new int[,]
        {
            { 1, 2, 3 },
            { 4, 5, 6 }
        };
 
        // Display the array elements
        for (int i = 0; i < matrix.GetLength(0); i++)
        {
            for (int j = 0; j < matrix.GetLength(1); j++)
            {
                Console.Write(matrix[i, j] + "\t");
            }
            Console.WriteLine();
        }
    }
}

Access and change

int[,] numbers = { {1, 4, 2}, {3, 6, 8} };
Console.WriteLine(numbers[0, 2]);  // Outputs 2
 
numbers[0, 0] = 5;  // Change value to 5
Console.WriteLine(numbers[0, 0]); // Outputs 5 instead of 1

Loop through 2D array

int[,] numbers = { {1, 4, 2}, {3, 6, 8} };
 
foreach (int i in numbers)
{
  Console.WriteLine(i);
}

Length

هناك كنا بنستخدم Length انما هنا هنستخدم GetLength()

int[,] numbers = { {1, 4, 2}, {3, 6, 8} };
 
for (int i = 0; i < numbers.GetLength(0); i++) 
{ 
  for (int j = 0; j < numbers.GetLength(1); j++) 
  { 
    Console.WriteLine(numbers[i, j]); 
  } 
}

Jagged Array

C# Jagged Array

Graph View

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