Csharp/CSharp Tutorial/Data Structure/Array Length

Array sizes and dimensions.

<source lang="csharp">using System; class MainClass {

   public static void PrintArray(int[] arr) {
       for (int i = 0; i < arr.Length; ++i)
           Console.WriteLine("OneDArray Row {0} = {1}", i, arr[i]);
   }
   public static void PrintArrayRank(int[,] arr) {
       Console.WriteLine("PrintArrayRank: {0} dimensions", arr.Rank);
   }

   public static void Main() {
       int[] x = new int[10];
       for (int i = 0; i < 10; ++i)
           x[i] = i;
       PrintArray(x);
       int[,] y = new int[10, 20];
       for (int k = 0; k < 10; ++k)
           for (int i = 0; i < 20; ++i)
               y[k, i] = i * k;
       PrintArrayRank(y);
   }

}</source>

Defining the Array Size at Runtime

<source lang="csharp">class MainClass {

 static void Main()
 {
   string[] groceryList;
   System.Console.Write("How many items on the list? ");
   int size = int.Parse(System.Console.ReadLine());
   groceryList = new string[size];
 }

}</source>

Use the GetLength() method to get number of elements in each dimension of the two dimensional array

<source lang="csharp">using System; class MainClass {

 public static void Main()
 {
   string[,] names = {
     {"J", "M", "P"},
     {"S", "E", "S"},
     {"C", "A", "W"},
     {"G", "P", "J"},
   };
   int numberOfRows = names.GetLength(0);
   int numberOfColumns = names.GetLength(1);
   Console.WriteLine("Number of rows = " + numberOfRows);
   Console.WriteLine("Number of columns = " + numberOfColumns);
 }

}</source>

Number of rows = 4
Number of columns = 3

Use the Length array property

<source lang="csharp">using System;

class MainClass {

 public static void Main() {  
   int[] nums = new int[10];  

   Console.WriteLine("Length of nums is " + nums.Length);  
 
   Console.Write("use Length to initialize nums");
   for(int i=0; i < nums.Length; i++)  
     nums[i] = i * i;  
 
   Console.Write("now use Length to display nums");
   Console.Write("Here is nums: "); 
   for(int i=0; i < nums.Length; i++)  
     Console.Write(nums[i] + " ");  
 }  

}</source>

Length of nums is 10
use Length to initialize numsnow use Length to display numsHere is nums: 0 1 4 9 16 25 36 49 64 81 "

Use the Length array property on a 3-D array

<source lang="csharp">using System;

class MainClass {

 public static void Main() {  
   int[,,] nums = new int[10, 5, 6];  

   Console.WriteLine("Length of nums is " + nums.Length);  
 
 }  

}</source>

Length of nums is 300

Using Length - 1 in the Array Index

<source lang="csharp">class MainClass {

 static void Main()
 {
   string[] languages = new string[9];
   languages[4] = languages[languages.Length - 1];
 }

}</source>