Reverse a String using Stack

Last Updated : 04 Apr, 2025

Given a string str, the task is to reverse it using stack.

Example:

Input: s = “GeeksQuiz”
Output: ziuQskeeG
Input: s = “abc”
Output: cba

Also read: Reverse a String – Complete Tutorial.

As we all know, stacks work on the principle of first in, last out. After popping all the elements and placing them back into the string, the former string would be reversed.

Follow the steps given below to reverse a string using stack.

Create an empty stack.
One by one push all characters of string to stack.
One by one pop all characters from stack and put them back to string.

C++

#include <iostream>
#include <stack>
using namespace std;

string reverse(string s) {
    stack<char> st;
    
    // Push all characters onto the stack
    for (char c : s)
        st.push(c);
    
    // Pop characters to form reversed string
    string res;
    while (!st.empty()) {
        res += st.top();
        st.pop();
    }
    return res;
}

int main() {
    string s = "geeksforgeeks";
    cout << s << endl;
    cout << reverse(s) << endl;
    return 0;
}

#include <stdio.h>
#include <string.h>

void reverse(char* s) {
    int n = strlen(s);
    for (int i = 0; i < n / 2; i++) {
        char temp = s[i];
        s[i] = s[n - i - 1];
        s[n - i - 1] = temp;
    }
}

int main() {
    char s[] = "geeksforgeeks";
    printf("%s\n", s);
    reverse(s);
    printf("%s\n", s);
    return 0;
}

Java

import java.util.Stack;

public class GfG {
    public static String reverse(String s) {
        Stack<Character> stack = new Stack<>();
        // Push all characters onto the stack
        for (char c : s.toCharArray())
            stack.push(c);
        // Pop characters to form reversed string
        StringBuilder res = new StringBuilder();
        while (!stack.isEmpty()) {
            res.append(stack.pop());
        }
        return res.toString();
    }

    public static void main(String[] args) {
        String s = "geeksforgeeks";
        System.out.println(s);
        System.out.println(reverse(s));
    }
}

Python

def reverse(s):
    # Use slicing to reverse the string
    return s[::-1]

s = "geeksforgeeks"
print(s)
print(reverse(s))

using System;
using System.Collections.Generic;

class GfG {
    static string Reverse(string s) {
        Stack<char> stack = new Stack<char>();
        // Push all characters onto the stack
        foreach (char c in s)
            stack.Push(c);
        // Pop characters to form reversed string
        char[] res = new char[s.Length];
        int i = 0;
        while (stack.Count > 0) {
            res[i++] = stack.Pop();
        }
        return new string(res);
    }

    static void Main() {
        string s = "geeksforgeeks";
        Console.WriteLine(s);
        Console.WriteLine(Reverse(s));
    }
}

JavaScript

function reverse(s) {
    // Convert string to array, reverse it, and join back to string
    return s.split('').reverse().join('');
}

let s = "geeksforgeeks";
console.log(s);
console.log(reverse(s));