Question

Write a C++ program to check whether a string is a palindrome. Input a string (word) from the keyboard. Assume the letters are case-insenstive. Use the C++ string class. Refer to the sample output below.

Sample Runs:

Enter a string: otto;

otto is a palindrome

Enter a string: A

A is a palindrome

Enter a string: heooh

heooh is not a palindrome

Answer 1

#include<string.h>
#include<iostream>

using namespace std;

bool isPalindrome(string input){

// Store size of string in len
int len = input.size();

// Set j to the last index
int j = len-1;

// Iterate loop from i = 0 to mid index
// If element at some index i is not equal to element at some index j
// Means string is not a palindrome, Return false, and loop will be terminated
// Otherwise, decrement j by 1, and compare other elements
for(int i =0;i<len/2;i++){
if(tolower(input[i])!=tolower(input[j])){
return false;
}
j--;
}
// Return true
return true;
}
int main()
{
// Ask user to enter a string
string input;
cout<<"Enter a string: ";
cin>>input;

// Call function to check if a string is palindrome
// and print message accordingly
if(isPalindrome(input)){
cout<<input<<" is a palindrome."<<endl;
}else{
cout<<input<<" is a not palindrome."<<endl;
}
return 0;
}

OUTPUT-