Question

C++ Programming

Palindrome Detector:

A palindrome is any word, phrase, or sentence that reads the same forward and backward. Here are some well-known palindromes:

Able was I, ere I saw Elba

A man,a plan, a canal, Panama

Desserts, I stressed

Kayak

Write a book function that uses recursion to determine if a string argument is a palindrome. The function should return true if the argument reads the same forward and backward. Demonstrate the function in a program, which continues to ask the user to type a text, and then print out the text is palindrome or not, until the user wants to quit the program. (Note: you might delete any punctuation signs firstly, only need to consider the letters)

(C++ Programming)

Answer 1

#include <iostream>

#include <cctype>

using namespace std;

//function declarations

bool testPalindrome(string str);

string upperCaseIt(string s);

int main()

{

//Declaring variables

string str,str1;

char ch;

  

/* This while loop continues to execute

* until the user enters other than 'y' or 'Y'

*/

while(true)

{

str1="";

//Getting the input entered by the user

cout<<"\nEnter a string :";

getline(cin,str);

  

//eliminating spaces,commas..etc

for(int i=0;i<str.length();i++)

{

if(isalpha(str[i]))

str1+=str[i];

}

//calling the function

str1=upperCaseIt(str1);

//calling the function

if(testPalindrome(str1))

cout<<"This is a Palindrome"<<endl;

else

cout<<"This is not a Palindrome"<<endl;  

cout<<"\nDo you Want to continue(Y/N):";

cin>>ch;

if(ch=='y'||ch=='Y')

{

cin.ignore();

continue;

}else

{

break;

}

}

return 0;

}

/* This is a recursive function which calculates

* whether the String is Palindrome or not using recursive method

* Param:string

* return: boolean

*/

bool testPalindrome(string str) {

if(str.length() == 0 || str.length() == 1)

return true;

else if(str[0] == str[str.length()-1])

return testPalindrome(str.substr(1, str.length()-2));

  

return false;

}

// This function will convert the lower case to upper case

string upperCaseIt(string s)

{

for (int i = 0; i < s.size(); i++)

{

if (s.at(i) >= 97 && s.at(i) <= 122)

{

s.at(i) = s.at(i) - 32;

}

}

return s;

}

_____________________

Output:

ב c:\ CAProgram Files (x86) Dev-CpplMinGW641bin\PlaindromelrrespectiveOfSpacesCommaR Files Enter a string Able was I. ere I saw Elba his is a Pali Do you Want to continue CY/N>:y Enter a string A man a plan. a canal. Panama his is a Pali Do you Want to continue CY/N>:y Enter a string Desserts. I stressed This is a Pal Do you want to continue(Y/N);y Enter a string Kayak This is a Pal Do you want to continue(Y/N):n Process exited after 54.7 seconds with return value 0 Press any key to continue . - .

______________Thank You