How to Reverse a Word Using Stack in C++?

In C++, we have a stack data structure that follows the Last In First Out (LIFO) principle. In this article, we will learn how to reverse a word using a stack in C++.

Example:

Input:
word = "GeeksforGeeks"

Output:
Reversed Word: skeeGrofskeeG

Reverse a String Using Stack in C++

To reverse a word using a stack in C++, we can push each character of the word onto the stack and then pop them off. Since a stack is a LIFO data structure, the characters will be popped off in the reverse order they were pushed on, effectively reversing the word.

Approach

• First, create an empty stack.
• Now, push all characters of the word to the stack.
• Start popping the characters from the stack and store them back in the reversed_word.
• Finally, we get the reversed word in reversed_word.

C++ Program to Reverse a String Using Stack

The below example demonstrates how we can reverse a word using a stack in C++.

// C++ Program to illustrate how to reverse a word using a
// stack
#include <iostream>
#include <stack>
using namespace std;

int main()
{
    // Declaring and initializing the original word
    string word = "GeeksforGeeks";
    cout << "Original Word: " << word << endl;

    // Creating a stack to store characters
    stack<char> s;

    // Push each character of the word onto the stack
    for (char c : word) {
        s.push(c);
    }

    // Declaring a string to store the reversed word
    string reversed_word = "";

    // Pop each character from the stack and append it to
    // the reversed word
    while (!s.empty()) {
        reversed_word += s.top();
        s.pop();
    }

    // Print the reversed word
    cout << "Reversed Word: " << reversed_word << endl;

    return 0;
}

Original Word: GeeksforGeeks
Reversed Word: skeeGrofskeeG

Time Complexity: O(N), where N is the length of word.
Auxiliary Space: O(N)