# Remove spaces from a given string

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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