C++ || Snippet – Palindrome Checker Using A Stack & Queue
![](https://www.programmingnotes.org/wp-content/uploads/2012/02/Snippet2.jpg)
This page consists of a sample program which demonstrates how to use a stack and a queue to test for a palindrome. This program is great practice for understanding how the two data structures work.
REQUIRED KNOWLEDGE FOR THIS PROGRAM
Structs
Classes
Template Classes - What Are They?
Stacks
Queues
LIFO - Last In First Out
FIFO - First In First Out
#include 'SingleQueue.h'
#include 'ClassStackListType.h'
This program first asks the user to enter in text which they wish to compare for similarity. The data is then saved into the system using the “enqueue” and “push” functions available within the queue and stack classes. After the data is obtained, a while loop is used to iterate through both classes, checking to see if the characters at each location within both classes are the same. If the text within both classes are the same, it is a palindrome.
NOTE: This program uses two custom template.h classes. To obtain the code for both class, click here and here.
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// ============================================================================ // Author: Kenneth Perkins // Date: Jul 22, 2012 // Taken From: http://programmingnotes.org/ // File: palindrome.cpp // Description: Demonstrates a palindrome checker using a stack & queue // ============================================================================ #include <iostream> #include <cctype> #include "SingleQueue.h" #include "ClassStackListType.h" using namespace std; int main() { // declare variable char singleChar = ' '; bool isPalindrome = true; SingleQueue<char> queue; StackListType<char> stack; // get data from user, then place them into the // queue and stack for storage. This loop also // displays the user input back to the screen via cout cout <<"Enter in some text to see if its a palindrome: "; while(cin.get(singleChar) && singleChar != '\n') { cout<<singleChar; queue.EnQueue(toupper(singleChar)); stack.Push(toupper(singleChar)); } // determine if the string is a palindrome while((!queue.IsEmpty() && !stack.IsEmpty()) && isPalindrome) { if(queue.Front() != stack.Top()) { isPalindrome = false; } else { queue.DeQueue(); stack.Pop(); } } // display results to the screen if(isPalindrome) { cout<<" is a palindrome!\n"; } else { cout<<" is NOT a palindrome..\n"; } return 0; }// http://programmingnotes.org/ |
QUICK NOTES:
The highlighted lines are sections of interest to look out for.
The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.
Once compiled, you should get this as your output
(Note: The code was compiled 2 separate times to demonstrate different output)
====== RUN 1 ======
Enter in some text to see if its a palindrome: StEP on No pETS
StEP on No pETS is a palindrome!
====== RUN 2 ======
Enter in some text to see if its a palindrome: Hello World
Hello World is NOT a palindrome..
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