Stack – Reverse a String using Stack

Introduction

Learn how to reverse a String using Stack. In this example takes in an array based Stack.

Stack – Data Structure – Array-based and Linked list based implementation.

The followings are the steps to reversing a String using Stack.

1. String to Char[].
2. Create a Stack.
3. Push all characters, one by one.
4. Then Pop all characters, one by one and put into the char[].
5. Finally, convert to the String.

public static String reverse(String str) {
        char[] charArr = str.toCharArray();
        int size = charArr.length;
        Stack stack = new Stack(size);

        int i;
        for(i = 0; i < size; ++i) {
            stack.push(charArr[i]);
        }

        for(i = 0; i < size; ++i) {
            charArr[i] = stack.pop();
        }

        return String.valueOf(charArr);
}

Time complexity – O(n)

Space complexity – O(n)

Complete Example

Original post : - http://mydevgeek.com/stack-reverse-string-using-stack/