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Remove spaces from a given string
• Difficulty Level : Easy
• Last Updated : 02 Jul, 2019

Given a string, remove all spaces from the string and return it.

```Input:  "g  eeks   for ge  eeks  "
Output: "geeksforgeeks"```

Expected time complexity is O(n) and only one traversal of string.

## We strongly recommend that you click here and practice it, before moving on to the solution.

Below is a Simple Solution

```1) Iterate through all characters of given string, do following
a) If current character is a space, then move all subsequent
characters one position back and decrease length of the
result string.
```

Time complexity of above solution is O(n2).

A Better Solution can solve it in O(n) time. The idea is to keep track of count of non-space character seen so far.

```1) Initialize 'count' = 0 (Count of non-space character seen so far)
2) Iterate through all characters of given string, do following
a) If current character is non-space, then put this character
at index 'count' and increment 'count'
3) Finally, put '\0' at index 'count'
```

Below is the implementation of above algorithm.

## C++

 `// An efficient C++ program to remove all spaces``// from a string``#include ``using` `namespace` `std;`` ` `// Function to remove all spaces from a given string``void` `removeSpaces(``char` `*str)``{``    ``// To keep track of non-space character count``    ``int` `count = 0;`` ` `    ``// Traverse the given string. If current character``    ``// is not space, then place it at index 'count++'``    ``for` `(``int` `i = 0; str[i]; i++)``        ``if` `(str[i] != ``' '``)``            ``str[count++] = str[i]; ``// here count is``                                   ``// incremented``    ``str[count] = ``'\0'``;``}`` ` `// Driver program to test above function``int` `main()``{``    ``char` `str[] = ``"g  eeks   for ge  eeks  "``;``    ``removeSpaces(str);``    ``cout << str;``    ``return` `0;``}`

## Java

 `     ` `// An efficient Java program to remove all spaces``// from a string``class` `GFG``{`` ` `// Function to remove all spaces ``// from a given string``static` `int` `removeSpaces(``char` `[]str)``{``    ``// To keep track of non-space character count``    ``int` `count = ``0``;`` ` `    ``// Traverse the given string.``    ``// If current character``    ``// is not space, then place ``    ``// it at index 'count++'``    ``for` `(``int` `i = ``0``; i

## Python

 `# Python program to Remove spaces from a given string`` ` `# Function to remove all spaces from a given string``def` `removeSpaces(string):`` ` `    ``# To keep track of non-space character count``    ``count ``=` `0`` ` `    ``list` `=` `[]`` ` `    ``# Traverse the given string. If current character``    ``# is not space, then place it at index 'count++'``    ``for` `i ``in` `xrange``(``len``(string)):``        ``if` `string[i] !``=` `' '``:``            ``list``.append(string[i])`` ` `    ``return` `toString(``list``)`` ` `# Utility Function``def` `toString(``List``):``    ``return` `''.join(``List``)`` ` `# Driver program``string ``=` `"g  eeks  for ge  eeks  "``print` `removeSpaces(string)`` ` `# This code is contributed by Bhavya Jain`

## C#

 `// An efficient C# program to remove all ``// spaces from a string ``using` `System;`` ` `class` `GFG ``{ `` ` `// Function to remove all spaces ``// from a given string ``static` `int` `removeSpaces(``char` `[]str) ``{ ``    ``// To keep track of non-space ``    ``// character count ``    ``int` `count = 0; `` ` `    ``// Traverse the given string. If current``    ``// character is not space, then place ``    ``// it at index 'count++' ``    ``for` `(``int` `i = 0; i < str.Length; i++) ``        ``if` `(str[i] != ``' '``) ``            ``str[count++] = str[i]; ``// here count is ``                                   ``// incremented `` ` `    ``return` `count; ``} `` ` `// Driver code ``public` `static` `void` `Main(String[] args) ``{ ``    ``char` `[]str = ``"g eeks for ge eeks "``.ToCharArray(); ``    ``int` `i = removeSpaces(str); ``    ``Console.WriteLine(String.Join(``""``, str).Substring(0, i)); ``} ``} `` ` `// This code is contributed by 29AjayKumar`

Output:
`geeksforgeeeks`

Time complexity of above solution is O(n) and it does only one traversal of string.
Another solution suggested by Divyam Madaan is to use predefined functions. Here is the implementation:

## C/C++

 `// CPP program to Remove spaces ``// from a given string``  ` `#include ``#include ``using` `namespace` `std;`` ` `// Function to remove all spaces from a given string``string removeSpaces(string str) ``{``    ``str.erase(``remove``(str.begin(), str.end(), ``' '``), str.end());``    ``return` `str;``}`` ` `// Driver program to test above function``int` `main() ``{``    ``string str = ``"g  eeks   for ge  eeks   "``;``    ``str = removeSpaces(str);``    ``cout << str;``    ``return` `0;``}`` ` `// This code is contributed by Divyam Madaan`

## Java

 `// Java program to remove ``// all spaces from a string`` ` `class` `GFG {``     ` `    ``// Function to remove all ``    ``// spaces from a given string``    ``static` `String removeSpace(String str)``    ``{``        ``str = str.replaceAll(``"\\s"``,``""``);``        ``return` `str;``    ``}`` ` `    ``// Driver Code``    ``public` `static` `void` `main(String args[])``    ``{``        ``String str = ``"g eeks for ge eeks "``;``        ``System.out.println(removeSpace(str));``    ``}``}`` ` `// This code is contributed by Kanhaiya.`

## Python

 `# Python program to Remove spaces from a given string``  ` `# Function to remove all spaces from a given string``def` `removeSpaces(string):``    ``string ``=` `string.replace(``' '``,'')``    ``return` `string``     ` `# Driver program``string ``=` `"g  eeks  for ge  eeks  "``print``(removeSpaces(string))`` ` `# This code is contributed by Divyam Madaan`

## C#

 `// C# program to remove ``// all spaces from a string ``using` `System;`` ` `class` `GFG ``{ ``     ` `    ``// Function to remove all ``    ``// spaces from a given string ``    ``static` `String removeSpace(String str) ``    ``{ ``        ``str = str.Replace(``" "``,``""``); ``        ``return` `str; ``    ``} `` ` `    ``// Driver Code ``    ``public` `static` `void` `Main() ``    ``{ ``        ``String str = ``"g eeks for ge eeks "``; ``        ``Console.WriteLine(removeSpace(str)); ``    ``} ``} `` ` `// This code is contributed by ``// PrinciRaj1992 `

Output:
`geeksforgeeeks`

Thanks to Souravi Sarkar for suggesting this problem and initial solution.

Java | Removing whitespaces using Regex

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