Remove spaces from a given string

Last Updated : 26 Mar, 2026

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

Examples:

Input: s = "g eeks for ge eeks "
Output: "geeksforgeeks"

Input: s = "abc d "
Output: "abcd"

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Table of Content

[Naive Approach] Using Brute Force - O(n*n) Time and O(1) Space

Traverse the string and whenever a space is found, shift all the following characters one position to the left and reduce the effective length of the string.

C++ 
#include <iostream>
#include <string>
using namespace std;

string removeSpaces(string s) {
    int n = s.length();

    for (int i = 0; i < n; i++) {
        if (s[i] == ' ') {

            // shift all characters left
            for (int j = i; j < n - 1; j++) {
                s[j] = s[j + 1];
            }
            n--;    
            i--;   
        }
    }

    // return string up to new length
    return s.substr(0, n);
}

int main() {
    string s = "g  eeks   for ge  eeks  ";
    cout << removeSpaces(s);
    return 0;
}
C 
#include <stdio.h>
#include <string.h>

char* removeSpaces(char s[]) {
    int n = strlen(s);

    for (int i = 0; i < n; i++) {
        if (s[i] == ' ') {

            // shift all characters left
            for (int j = i; j < n - 1; j++) {
                s[j] = s[j + 1];
            }
            n--;
            i--;
        }
    }

    s[n] = '\0';  // terminate string
    return s;
}

int main() {
    char s[] = "g  eeks   for ge  eeks  ";
    printf("%s", removeSpaces(s));
    return 0;
}
Java 
class GFG {

    static String removeSpaces(String s) {
        char[] arr = s.toCharArray();
        int n = arr.length;

        for (int i = 0; i < n; i++) {
            if (arr[i] == ' ') {

                // shift all characters left
                for (int j = i; j < n - 1; j++) {
                    arr[j] = arr[j + 1];
                }
                n--;
                i--;
            }
        }

        return new String(arr, 0, n); // return valid part
    }

    public static void main(String[] args) {
        String s = "g  eeks   for ge  eeks  ";
        System.out.print(removeSpaces(s));
    }
}
Python 
def removeSpaces(s):
    res = []

    for ch in s:
        if ch != ' ':
            res.append(ch)

    return "".join(res)


if __name__ == "__main__":
    s = "g  eeks   for ge  eeks  "
    print(removeSpaces(s))
C# 
using System;

class GFG {

    static string RemoveSpaces(string s) {
        char[] arr = s.ToCharArray();
        int n = arr.Length;

        for (int i = 0; i < n; i++) {
            if (arr[i] == ' ') {

                // shift all characters left
                for (int j = i; j < n - 1; j++) {
                    arr[j] = arr[j + 1];
                }
                n--;
                i--;
            }
        }

        return new string(arr, 0, n); // return valid part
    }

    static void Main() {
        string s = "g  eeks   for ge  eeks  ";
        Console.Write(RemoveSpaces(s));
    }
}
JavaScript 
function removeSpaces(s) {
    s = s.split('');
    let n = s.length;

    for (let i = 0; i < n; i++) {
        if (s[i] === ' ') {

            // shift all characters left
            for (let j = i; j < n - 1; j++) {
                s[j] = s[j + 1];
            }
            n--;
            i--;
        }
    }

    return s.slice(0, n).join(""); // return result
}

// Driver code
let s = "g  eeks   for ge  eeks  ";
console.log(removeSpaces(s));

Output
geeksforgeeeks

[Expected Approach] Using Two Pointer - O(n) Time and O(1) Space

Traverse the string using two indices, where one index reads each character and the other writes only non-space characters. Whenever a non-space character is found, place it at the write index and move both pointers accordingly. This way, all non-space characters are shifted forward without using extra space.

C++ 
#include <iostream>
#include <string>
using namespace std;

string removeSpaces(string s) {
    int n = s.length();
    int j = 0;  // write index

    for (int i = 0; i < n; i++) {
        if (s[i] != ' ') {
            s[j++] = s[i];
        }
    }

    return s.substr(0, j);
}

int main() {
    string s = "g  eeks   for ge  eeks  ";
    cout << removeSpaces(s);
    return 0;
}
C 
#include <stdio.h>
#include <string.h>

char* removeSpaces(char s[]) {
    int j = 0;

    for (int i = 0; s[i] != '\0'; i++) {
        if (s[i] != ' ') {
            s[j++] = s[i];
        }
    }

    s[j] = '\0';
    return s;
}

int main() {
    char s[] = "g  eeks   for ge  eeks  ";
    printf("%s", removeSpaces(s));
    return 0;
}
Java 
class GFG {

    static String removeSpaces(String s) {
        char[] arr = s.toCharArray();
        int j = 0;

        for (int i = 0; i < arr.length; i++) {
            if (arr[i] != ' ') {
                arr[j++] = arr[i];
            }
        }

        return new String(arr, 0, j);
    }

    public static void main(String[] args) {
        String s = "g  eeks   for ge  eeks  ";
        System.out.print(removeSpaces(s));
    }
}
Python 
def removeSpaces(s):
    res = []

    for ch in s:
        if ch != ' ':
            res.append(ch)

    return "".join(res)


if __name__ == "__main__":
    s = "g  eeks   for ge  eeks  "
    print(removeSpaces(s))
C# 
using System;

class GFG {

    static string RemoveSpaces(string s) {
        char[] arr = s.ToCharArray();
        int j = 0;

        for (int i = 0; i < arr.Length; i++) {
            if (arr[i] != ' ') {
                arr[j++] = arr[i];
            }
        }

        return new string(arr, 0, j);
    }

    static void Main() {
        string s = "g  eeks   for ge  eeks  ";
        Console.Write(RemoveSpaces(s));
    }
}
JavaScript 
function removeSpaces(s) {
    let arr = s.split('');
    let j = 0;

    for (let i = 0; i < arr.length; i++) {
        if (arr[i] !== ' ') {
            arr[j++] = arr[i];
        }
    }

    return arr.slice(0, j).join("");
}

// Driver code
let s = "g  eeks   for ge  eeks  ";
console.log(removeSpaces(s));

Output
geeksforgeeeks

Using Built-in functions - O(n) Time and O(1) Space

Use the built-in remove() function to shift all non-space characters to the front of the string while returning the new logical end. Then use erase() to remove the remaining unwanted part of the string. This avoids manual shifting and processes each character only once.

C++ 
#include <iostream>
#include <algorithm>
using namespace std;

// Function to remove all spaces
string removeSpaces(string s) {
    // move non-space characters to front
    auto new_end = remove(s.begin(), s.end(), ' ');
    
    // erase extra part
    s.erase(new_end, s.end());
    
    return s;
}

int main() {
    string s = "g  eeks   for ge  eeks  ";
    cout << removeSpaces(s);
    return 0;
}
Java 
public class GFG {

    // Function to remove all spaces
    static String removeSpaces(String s) {
        // replace all spaces with empty string
        s = s.replace(" ", "");
        return s;
    }

    public static void main(String[] args) {
        String s = "g  eeks   for ge  eeks  ";
        System.out.print(removeSpaces(s));
    }
}
Python 
def removeSpaces(s):
    # replace all spaces with empty string
    s = s.replace(" ", "")
    return s

if __name__ == "__main__":
    s = "g  eeks   for ge  eeks  "
    print(removeSpaces(s), end="")
C# 
using System;

class GFG {

    // Function to remove all spaces
    static string RemoveSpaces(string s) {
        // replace all spaces with empty string
        s = s.Replace(" ", "");
        return s;
    }

    static void Main() {
        string s = "g  eeks   for ge  eeks  ";
        Console.Write(RemoveSpaces(s));
    }
}
JavaScript 
function removeSpaces(s) {
    return s.replace(/ /g, "");
}

// Driver code
let s = "g  eeks   for ge  eeks  ";
console.log(removeSpaces(s));

Output
geeksforgeeeks

note: C does not have a built-in function to remove spaces, so it must be done manually.

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