# Search, insert and delete in an unsorted array

• Difficulty Level : Basic
• Last Updated : 28 Jan, 2022

In this post search, insert, and delete operations in an unsorted array are discussed.

Search Operation

In an unsorted array, the search operation can be performed by linear traversal from the first element to the last element.

## C++

 `// C++ program to implement linear``// search in unsorted array``#include``using` `namespace` `std;` `// Function to implement search operation``int` `findElement(``int` `arr[], ``int` `n,``                ``int` `key)``{``    ``int` `i;``    ``for` `(i = 0; i < n; i++)``        ``if` `(arr[i] == key)``            ``return` `i;` `    ``return` `-1;``}` `// Driver Code``int` `main()``{``    ``int` `arr[] = {12, 34, 10, 6, 40};``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);` `    ``// Using a last element as search element``    ``int` `key = 40;``    ``int` `position = findElement(arr, n, key);` `    ``if` `(position == - 1)``        ``cout << ``"Element not found"``;``    ``else``        ``cout << ``"Element Found at Position: "``             ``<< position + 1;` `    ``return` `0;``}` `// This code is contributed``// by Akanksha Rai`

## C

 `// C program to implement linear``// search in unsorted array``#include` `// Function to implement search operation``int` `findElement(``int` `arr[], ``int` `n,``                ``int` `key)``{``    ``int` `i;``    ``for` `(i = 0; i < n; i++)``        ``if` `(arr[i] == key)``            ``return` `i;` `    ``return` `-1;``}` `// Driver Code``int` `main()``{``    ``int` `arr[] = {12, 34, 10, 6, 40};``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);` `    ``// Using a last element as search element``    ``int` `key = 40;``    ``int` `position = findElement(arr, n, key);` `    ``if` `(position == - 1)``        ``printf``(``"Element not found"``);``    ``else``        ``printf``(``"Element Found at Position: %d"``, position + 1 );` `    ``return` `0;``}`

## Java

 `// Java program to implement linear``// search in unsorted arrays` `class` `Main``{``    ``// Function to implement``    ``// search operation``    ``static` `int` `findElement(``int` `arr[], ``int` `n,``                           ``int` `key)``    ``{``        ``for` `(``int` `i = ``0``; i < n; i++)``            ``if` `(arr[i] == key)``                ``return` `i;``     ` `        ``return` `-``1``;``    ``}``     ` `    ``// Driver Code``    ``public` `static` `void` `main(String args[])``    ``{``        ``int` `arr[] = {``12``, ``34``, ``10``, ``6``, ``40``};``        ``int` `n = arr.length;``     ` `        ``// Using a last element as search element``        ``int` `key = ``40``;``        ``int` `position = findElement(arr, n, key);``     ` `        ``if` `(position == - ``1``)``            ``System.out.println(``"Element not found"``);``        ``else``            ``System.out.println(``"Element Found at Position: "``                                ``+ (position + ``1``));``    ``}``}`

## Python3

 `# Python program for searching in``# unsorted array` `def` `findElement(arr, n, key):``    ``for` `i ``in` `range` `(n):``        ``if` `(arr[i] ``=``=` `key):``            ``return` `i``    ``return` `-``1`` ` `arr ``=` `[``12``, ``34``, ``10``, ``6``, ``40``]``key ``=` `40``n ``=` `len``(arr)`` ` `#search operation``index ``=` `findElement(arr, n, key)``if` `index !``=` `-``1``:``    ``print` `(``"element found at position: "` `+` `str``(index ``+` `1` `))``else``:``    ``print` `(``"element not found"``)``    ` `# Thanks to Aditi Sharma for contributing``# this code   `

## C#

 `// C# program to implement linear``// search in unsorted arrays``using` `System;` `class` `main``{``    ``// Function to implement``    ``// search operation``    ``static` `int` `findElement(``int` `[]arr, ``int` `n,``                           ``int` `key)``    ``{``        ``for` `(``int` `i = 0; i < n; i++)``            ``if` `(arr[i] == key)``                ``return` `i;``    ` `        ``return` `-1;``    ``}``    ` `    ``// Driver Code``    ``public` `static` `void` `Main()``    ``{``        ``int` `[]arr = {12, 34, 10, 6, 40};``        ``int` `n = arr.Length;``    ` `        ``// Using a last element as``        ``// search element``        ``int` `key =40;``        ``int` `position = findElement(arr,n,key);``    ` `        ``if` `(position == - 1)``        ``Console.WriteLine(``"Element not found"``);``        ``else``        ``Console.WriteLine(``"Element Found at Position: "``                            ``+ (position+1));``    ``}``}` `//  This code is contributed by vt_m.`

## PHP

 ``

## Javascript

 ``

Output:

`Element Found at Position: 5`

Insert at the end

In an unsorted array, the insert operation is faster as compared to a sorted array because we don’t have to care about the position at which the element is to be placed.

## C++

 `// C++ program to implement insert``// operation in an unsorted array.``#include ``using` `namespace` `std;` `// Inserts a key in arr[] of given capacity.``// n is current size of arr[]. This``// function returns n + 1 if insertion``// is successful, else n.``int` `insertSorted(``int` `arr[], ``int` `n,``                ``int` `key,``                ``int` `capacity)``{` `    ``// Cannot insert more elements if n is``    ``// already more than or equal to capacity``    ``if` `(n >= capacity)``    ``return` `n;` `    ``arr[n] = key;` `    ``return` `(n + 1);``}` `// Driver Code``int` `main()``{``    ``int` `arr[20] = {12, 16, 20, 40, 50, 70};``    ``int` `capacity = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ``int` `n = 6;``    ``int` `i, key = 26;` `    ``cout << ``"\n Before Insertion: "``;``    ``for` `(i = 0; i < n; i++)``        ``cout << arr[i]<< ``" "``;` `    ``// Inserting key``    ``n = insertSorted(arr, n, key, capacity);` `    ``cout << ``"\n After Insertion: "``;``    ``for` `(i = 0; i < n; i++)``        ``cout << arr[i] << ``" "``;` `    ``return` `0;``}` `// This code is contributed by SHUBHAMSINGH10`

## C

 `// C program to implement insert``// operation in an unsorted array.``#include` `// Inserts a key in arr[] of given capacity.``// n is current size of arr[]. This``// function returns n + 1 if insertion``// is successful, else n.``int` `insertSorted(``int` `arr[], ``int` `n,``                 ``int` `key,``                 ``int` `capacity)``{` `    ``// Cannot insert more elements if n is``    ``// already more than or equal to capacity``    ``if` `(n >= capacity)``       ``return` `n;` `    ``arr[n] = key;` `    ``return` `(n + 1);``}` `// Driver Code``int` `main()``{``    ``int` `arr[20] = {12, 16, 20, 40, 50, 70};``    ``int` `capacity = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ``int` `n = 6;``    ``int` `i, key = 26;` `    ``printf``(``"\n Before Insertion: "``);``    ``for` `(i = 0; i < n; i++)``        ``printf``(``"%d  "``, arr[i]);` `    ``// Inserting key``    ``n = insertSorted(arr, n, key, capacity);` `    ``printf``(``"\n After Insertion: "``);``    ``for` `(i = 0; i < n; i++)``        ``printf``(``"%d  "``,arr[i]);` `    ``return` `0;``}`

## Java

 `// Java program to implement insert``// operation in an unsorted array.` `class` `Main``{``    ``// Function to insert a given key in``    ``// the array. This function returns n+1``    ``// if insertion is successful, else n.``    ``static` `int` `insertSorted(``int` `arr[], ``int` `n,``                            ``int` `key,``                            ``int` `capacity)``    ``{` `        ``// Cannot insert more elements if n``        ``// is already more than or equal to``        ``// capacity``        ``if` `(n >= capacity)``           ``return` `n;``     ` `        ``arr[n] = key;``     ` `        ``return` `(n + ``1``);``    ``}``     ` `    ``// Driver Code``    ``public` `static` `void` `main (String[] args)``    ``{  ``        ``int``[] arr = ``new` `int``[``20``];``        ``arr[``0``] = ``12``;``        ``arr[``1``] = ``16``;``        ``arr[``2``] = ``20``;``        ``arr[``3``] = ``40``;``        ``arr[``4``] = ``50``;``        ``arr[``5``] = ``70``;``        ``int` `capacity = ``20``;``        ``int` `n = ``6``;``        ``int` `i, key = ``26``;``     ` `        ``System.out.print(``"Before Insertion: "``);``        ``for` `(i = ``0``; i < n; i++)``            ``System.out.print(arr[i]+``" "``);``     ` `        ``// Inserting key``        ``n = insertSorted(arr, n, key, capacity);``     ` `        ``System.out.print(``"\n After Insertion: "``);``        ``for` `(i = ``0``; i < n; i++)``            ``System.out.print(arr[i]+``" "``);``    ``}``}`

## Python3

 `# Python program for inserting``# an element in an unsorted array` `# method to insert element``def` `insert(arr, element):``    ``arr.append(element)` `# declaring array and key to insert``arr ``=` `[``12``, ``16``, ``20``, ``40``, ``50``, ``70``]``key ``=` `26`` ` `# array before inserting an element``print` `(``"Before Inserting: "``)``print` `(arr)`` ` `# array after Inserting element``insert(arr, key)``print``(``"After Inserting: "``)``print` `(arr)` `# Thanks to Aditi Sharma for contributing``# this code   `

## C#

 `// C# program to implement insert``// operation in an unsorted array.``using` `System;` `class` `main``{``    ` `    ``// Function to insert a given``    ``// key in the array. This``    ``// function  returns n + 1``    ``// if insertion is successful,``    ``// else n.``    ``static` `int` `insertSorted(``int` `[]arr, ``int` `n,``                            ``int` `key,``                            ``int` `capacity)``    ``{``        ` `        ``// Cannot insert more elements``        ``// if n is already more than``        ``// or equal to capacity``        ``if` `(n >= capacity)``        ``return` `n;``    ` `        ``arr[n] = key;``        ``return` `(n + 1);``    ``}``    ` `    ``// Driver Code``    ``public` `static` `void` `Main ()``    ``{``        ``int``[] arr = ``new` `int``[20];``        ``arr[0] = 12;``        ``arr[1] = 16;``        ``arr[2] = 20;``        ``arr[3] = 40;``        ``arr[4] = 50;``        ``arr[5] = 70;``        ``int` `capacity = 20;``        ``int` `n = 6;``        ``int` `i, key = 26;``    ` `        ``Console.Write(``"Before Insertion: "``);``        ``for` `(i = 0; i < n; i++)``            ``Console.Write(arr[i]+``" "``);``            ``Console.WriteLine();``    ` `        ``// Inserting key``        ``n = insertSorted(arr, n, key, capacity);``    ` `        ``Console.Write(``"After Insertion: "``);``        ``for` `(i = 0; i < n; i++)``            ``Console.Write(arr[i]+``" "``);``            ` `    ``}``}` `// This code is contributed by vt_m.`

## PHP

 `= ``\$capacity``)``        ``return` `\$n``;` `    ``array_push``(``\$arr``, ``\$key``);` `    ``return` `(``\$n` `+ 1);``}` `// Driver Code` `\$arr` `= ``array``(12, 16, 20, 40, 50, 70);``\$capacity` `= 20;``\$n` `= 6;``\$key` `= 26;` `echo` `"Before Insertion: "``;``for` `(``\$i` `= 0; ``\$i` `< ``\$n``; ``\$i``++)``    ``echo` `\$arr``[``\$i``] . ``" "``;` `// Inserting key``\$n` `= insertSorted(``\$arr``, ``\$n``,``                  ``\$key``, ``\$capacity``);` `echo` `"\nAfter Insertion: "``;``for` `(``\$i` `= 0; ``\$i` `< ``\$n``; ``\$i``++)``    ``echo` `\$arr``[``\$i``] . ``" "``;``    ` `// This code is contributed by``// Rajput-Ji``?>`

## Javascript

 ``

Output:

```Before Insertion: 12 16 20 40 50 70
After Insertion: 12 16 20 40 50 70 26 ```

Delete Operation

In the delete operation, the element to be deleted is searched using the linear search, and then delete operation is performed followed by shifting the elements.

## C++

 `// C++ program to implement delete operation in a``// unsorted array``#include ``using` `namespace` `std;` `// To search a key to be deleted``int` `findElement(``int` `arr[], ``int` `n,``                ``int` `key);` `// Function to delete an element``int` `deleteElement(``int` `arr[], ``int` `n,``                ``int` `key)``{``    ``// Find position of element to be deleted``    ``int` `pos = findElement(arr, n, key);` `    ``if` `(pos == - 1)``    ``{``        ``cout << ``"Element not found"``;``        ``return` `n;``    ``}` `    ``// Deleting element``    ``int` `i;``    ``for` `(i = pos; i < n - 1; i++)``        ``arr[i] = arr[i + 1];` `    ``return` `n - 1;``}` `// Function to implement search operation``int` `findElement(``int` `arr[], ``int` `n, ``int` `key)``{``    ``int` `i;``    ``for` `(i = 0; i < n; i++)``        ``if` `(arr[i] == key)``            ``return` `i;` `    ``return` `- 1;``}` `// Driver code``int` `main()``{``    ``int` `i;``    ``int` `arr[] = {10, 50, 30, 40, 20};` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ``int` `key = 30;` `    ``cout << ``"Array before deletion\n"``;``    ``for` `(i = 0; i < n; i++)``    ``cout << arr[i] <<``" "` `;` `    ``n = deleteElement(arr, n, key);` `    ``cout << ``"\n\nArray after deletion\n"``;``    ``for` `(i = 0; i < n; i++)``    ``cout << arr[i] << ``" "``;` `    ``return` `0;``}` `// This code is contributed by shubhamsingh10`

## C

 `// C program to implement delete operation in a``// unsorted array``#include` `// To search a key to be deleted``int` `findElement(``int` `arr[], ``int` `n,``                ``int` `key);` `// Function to delete an element``int` `deleteElement(``int` `arr[], ``int` `n,``                  ``int` `key)``{``    ``// Find position of element to be deleted``    ``int` `pos = findElement(arr, n, key);` `    ``if` `(pos == - 1)``    ``{``        ``printf``(``"Element not found"``);``        ``return` `n;``    ``}` `    ``// Deleting element``    ``int` `i;``    ``for` `(i = pos; i < n - 1; i++)``        ``arr[i] = arr[i + 1];` `    ``return` `n - 1;``}` `// Function to implement search operation``int` `findElement(``int` `arr[], ``int` `n, ``int` `key)``{``    ``int` `i;``    ``for` `(i = 0; i < n; i++)``        ``if` `(arr[i] == key)``            ``return` `i;` `    ``return` `- 1;``}` `// Driver code``int` `main()``{``    ``int` `i;``    ``int` `arr[] = {10, 50, 30, 40, 20};` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ``int` `key = 30;` `    ``printf``(``"Array before deletion\n"``);``    ``for` `(i = 0; i < n; i++)``      ``printf``(``"%d  "``, arr[i]);` `    ``n = deleteElement(arr, n, key);` `    ``printf``(``"\nArray after deletion\n"``);``    ``for` `(i = 0; i < n; i++)``      ``printf``(``"%d  "``, arr[i]);` `    ``return` `0;``}`

## Java

 `// Java program to implement delete``// operation in an unsorted array`` ` `class` `Main``{``    ``// function to search a key to``    ``// be deleted``    ``static` `int` `findElement(``int` `arr[], ``int` `n, ``int` `key)``    ``{``        ``int` `i;``        ``for` `(i = ``0``; i < n; i++)``            ``if` `(arr[i] == key)``                ``return` `i;``     ` `        ``return` `-``1``;``    ``}``    ` `    ``// Function to delete an element``    ``static` `int` `deleteElement(``int` `arr[], ``int` `n, ``int` `key)``    ``{``        ``// Find position of element to be``        ``// deleted``        ``int` `pos = findElement(arr, n, key);``     ` `        ``if` `(pos == -``1``)``        ``{``            ``System.out.println(``"Element not found"``);``            ``return` `n;``        ``}``     ` `        ``// Deleting element``        ``int` `i;``        ``for` `(i = pos; i< n - ``1``; i++)``            ``arr[i] = arr[i + ``1``];``     ` `        ``return` `n - ``1``;``    ``}``     ` `    ``// Driver Code``    ``public` `static` `void` `main(String args[])``    ``{``        ``int` `i;``        ``int` `arr[] = {``10``, ``50``, ``30``, ``40``, ``20``};``     ` `        ``int` `n = arr.length;``        ``int` `key = ``30``;``     ` `        ``System.out.println(``"Array before deletion"``);``        ``for` `(i=``0``; i

## Python3

 `# Python program to delete an element``# from an unsorted array` `# Declaring array and key to delete``arr ``=` `[``10``, ``50``, ``30``, ``40``, ``20``]``key ``=` `30`` ` `print``(``"Array before deletion:"``)``print` `(arr)`` ` `# deletes key if found in the array``# otherwise shows error not in list``arr.remove(key)``print``(``"Array after deletion"``)``print``(arr)`` ` `# This code is contributed by Aditi Sharma.`

## C#

 `// C# program to implement delete``// operation in an unsorted array``using` `System;` `class` `main``{``    ``// Function to search a ``    ``// key to be deleted``    ``static` `int` `findElement(``int` `[]arr,``                           ``int` `n,``                           ``int` `key)``    ``{``        ` `        ``int` `i;``        ``for` `(i = 0; i < n; i++)``            ``if` `(arr[i] == key)``                ``return` `i;``    ` `        ``return` `-1;``    ``}``    ` `    ``// Function to delete an element``    ``static` `int` `deleteElement(``int` `[]arr,``                             ``int` `n,``                             ``int` `key)``    ``{``        ``// Find position of element``        ``// to be deleted``        ``int` `pos = findElement(arr, n, key);``    ` `        ``if` `(pos == - 1)``        ``{``            ``Console.WriteLine(``"Element not found"``);``            ``return` `n;``        ``}``    ` `        ``// Deleting element``        ``int` `i;``        ``for` `(i = pos; i < n - 1; i++)``            ``arr[i] = arr[i + 1];``    ` `        ``return` `n - 1;``    ``}``    ` `    ``// Driver Code``    ``public` `static` `void` `Main()``    ``{``        ``int` `i;``        ``int` `[]arr = {10, 50, 30, 40, 20};``    ` `        ``int` `n = arr.Length;``        ``int` `key = 30;``    ` `        ``Console.Write(``"Array before deletion "``);``        ``for` `(i = 0; i < n; i++)``        ``Console.Write(arr[i] + ``" "``);``        ``Console.WriteLine();``    ` `        ``n = deleteElement(arr, n, key);``    ` `        ``Console.Write(``"Array after deletion "``);``        ``for` `(i = 0; i < n; i++)``        ``Console.Write(arr[i]+``" "``);``    ``}``}` `// This code is contributed by vt_m.`

## PHP

 ``

## Javascript

 ``

Output:

```Array before deletion
10 50 30 40 20

Array after deletion
10 50 40 20 ```

Time complexities:
Search: O(n)
Insert: O(1)
Delete: O(n)

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