String Reverse String using Stack

Initialize an empty stack.
Push each character of the string onto the stack.
Pop the characters from the stack and append them to a new string.
The new string is the reversed version of the original string.

Below is the implementation of the above approach:

C++

// C++ program to reverse a string using stack
#include <bits/stdc++.h>
using namespace std;
 
void reversebyStack(string &str)
{
  // To store the characters of original string. 
   stack<char> st;
   for (int i=0; i<str.length(); i++)
     // Push the charcters into stack
       st.push(str[i]);
 
   for (int i=0; i<str.length(); i++) {
     // Pop the charcters of stack into the original string.
       str[i] = st.top();
       st.pop();
   }       
}
 
// Driver program
int main()
{
  // Original String
    string str = "w3wiki";
    reversebyStack(str);
    cout << str;
    return 0;
}

Java

// Java program to reverse a string using stack
import java.util.*;
class GFG
{
  public static String reversebyStack(char []str) 
 { 
   Stack<Character> st = new Stack<>(); 
   for(int i=0; i<str.length; i++) 
     // Push the charcters into stack
        st.push(str[i]); 
 
   for (int i=0; i<str.length; i++) { 
      // Pop the charcters of stack into the original string.
    str[i] = st.peek(); 
    st.pop(); 
   }     
   return String.valueOf(str);// converting character array to string
 } 
 
// Driver program 
   public static void main(String []args) 
   { 
      String str = "w3wiki"; 
      str = reversebyStack(str.toCharArray());// passing character array as parameter 
      System.out.println(str); 
   }
}
// This code is contributed by Adarsh_Verma

Python3

# Python program to reverse a string using stack
 
def reversebyStack(str):
     
    # using as stack
    stack = []
 
    for i in range(len(str)):
      # Push the charcters into stack
        stack.append(str[i])
     
    for i in range(len(str)):
       # Pop the charcters of stack into the original string.
        str[i] = stack.pop()
 
if __name__ == "__main__":
    str = "w3wiki"
 
    # converting string to list
    # because strings do not support
    # item assignment
    str = list(str)
    reversebyStack(str)
 
    # converting list to string
    str = ''.join(str)
    print(str)
     
# This code is contributed by
# sanjeev2552

C#

// C# program to reverse a string using stack 
using System;
using System.Collections.Generic;
 
class GFG 
{ 
    public static String reversebyStack(char []str) 
    { 
        Stack<char> st = new Stack<char>(); 
        for(int i = 0; i < str.Length; i++) 
          // Push the charcters into stack
            st.Push(str[i]); 
 
        for (int i = 0; i < str.Length; i++) 
        { 
           // Pop the charcters of stack into the original string.
            str[i] = st.Peek(); 
            st.Pop(); 
        } 
         
        // converting character array to string
        return String.Join("",str); 
    } 
 
    // Driver program 
    public static void Main() 
    { 
        String str = "w3wiki"; 
         
        // passing character array as parameter
        str = reversebyStack(str.ToCharArray()); 
        Console.WriteLine(str); 
    } 
} 
 
// This code is contributed by Rajput-Ji

Javascript

// Function to reverse a string using a stack
function reverseByStack(str) {
    // To store the characters of the original string.
    const stack = [];
 
    // Push the characters into the stack.
    for (let i = 0; i < str.length; i++) {
        stack.push(str[i]);
    }
 
    // Pop the characters of the stack and build the reversed string.
    let reversedStr = '';
    while (stack.length > 0) {
        reversedStr += stack.pop();
    }
 
    return reversedStr;
}
 
// Driver program
function main() {
    // Original String
    let str = "w3wiki";
    let reversedStr = reverseByStack(str);
    console.log(reversedStr);
}
 
main();
 
 
// This code is contributed by shivamgupta0987654321

Output

skeegrofskeeg

Time Complexity: O(n)
Auxiliary Space: O(n)

String Reverse in C/C++/Java/Python/JavaScript

String reverse or reverse a string means changing the position of each character of the given string to its opposite position from end, i.e. if a character is at position 1 then its new position will be String.length, similarly if a character is at position 2 then its new position will be String.length – 1, and so on.

String Reverse in C/C++/Java/Python/JavaScript

Given a string, write a program to reverse the string.

Input: original_string[] = Geeks
Output: string_reversed[] = skeeG

Input: original_string[] = w3wiki
Output: string_reversed[] = skeeGroFskeeG

Table of Content

Reverse String using a Loop:
Reverse String using inbuilt method
Reverse String using Recursion:
Reverse String using two pointers:
String Reverse String using Stack:

String Reverse String using Stack

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String Reverse in C/C++/Java/Python/JavaScript

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String Reverse String using Stack

C++

Java

Python3

C#

Javascript

String Reverse in C/C++/Java/Python/JavaScript

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