Resizing of arrays in C

manoj1808 — Fri, 14 May 2021 15:00:32 +0000

Array.Resize(T[], Int32) Method is used to resize the number of elements present in the array. Or in other words, this method is used to change the number of elements of a one-dimensional array to the specified new size. It resizes the only 1-D array, not multidimensional array.

Syntax:

public static void Resize (ref T[] array, int newSize);
Parameters:

array: It is a one-dimensional, zero-based array to resize, or null to create a new array with the specified size.
newsize: It is the size of the new array.

Exception:If the value of nsize is less than zero, then this method will give ArgumentOutOfRangeException.

Note: This method is an O(n) operation, where n is new size.

Below given are some examples to understand the implementation in a better way:

Example 1:

// C# program to resize the
// elements of the 1-D array

using System;

public class GFG {

// Main method 

static public void Main() 

{ 



    // create and initialize array 

    string[] myarray = {"C#", "Java", "C++", "Python", 

                         "HTML", "CSS", "JavaScript"}; 



    // Display original array before Resize 

    Console.WriteLine("Original Array:"); 



    foreach(string i in myarray) 

    { 

        Console.WriteLine(i); 

    } 



    int len = myarray.Length; 

    Console.WriteLine("Length of myarray: "+len); 

    Console.WriteLine(); 



    // Resize the element of myarray and  

    // create a new array. Here new array 

    // is smaller than the original array  

    // so, elements are copied from the  

    // myarray to the new array until the 

    // new one is filled. The rest of the 

    // elements in the old array are ignored 

    Array.Resize(ref myarray, len - 3); 



    Console.WriteLine("New array is less than myarray:"); 



    foreach(string j in myarray) 

    { 

        Console.WriteLine(j); 

    } 



}

}
Output:
Original Array:
C#
Java
C++
Python
HTML
CSS
JavaScript
Length of myarray: 7

New array is less than myarray:
C#
Java
C++
Python
Example 2:

// C# program to resize the

// elements of the 1-D array

using System;

public class GFG {

// Main method 

static public void Main() 

{ 



    // create and initialize array 

    string[] myarray = {"C#", "C++", "Ruby",  

                     "Java", "PHP", "Perl"}; 



    // Display original string before Resize 

    Console.WriteLine("Original Array:"); 



    foreach(string i in myarray) 

    { 

        Console.WriteLine(i); 

    } 



    // Length of old array 

    int len = myarray.Length; 

    Console.WriteLine("Length of myarray: "+len); 

    Console.WriteLine(); 



    // Resize the element of myarray  

    // and create a new array 

    // Here new array is greater than 

    // original array so, all the element  

    // from myarray is copied to new array 

    // and remaining will be null 

    Array.Resize(ref myarray, 10); 



    Console.WriteLine("New array is greater than myarray:"); 



    foreach(string j in myarray) 

    { 

        Console.WriteLine(j); 

    } 



    // Length of new array 

    int len1 = myarray.Length; 

    Console.WriteLine("Length of New Array: "+len1); 



}

}
Output:
Original Array:
C#
C++
Ruby
Java
PHP
Perl
Length of myarray: 6

New array is greater than myarray:
C#
C++
Ruby
Java
PHP
Perl

Length of New Array: 10

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Resizing of arrays in C