Problem: Write a C++ program to check whether a given string is a palindrome or not.
Example:
1 2 3 4 5 | Input: mom Output: Palindrome Input: Malayalam Output: Palindrome |
A palindrome string is that string which in reverse is equal to the original string.
To check palindrome string in C++:
- Input the string.
- Reverse the string.
- Check whether the reverse of the string is equal to the input string.
- If yes, then the string is a palindrome, or else it is not.
Here is the implementation of the steps in C++:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | #include <iostream> using namespace std; int main() { string str, rev=""; //Input String cout<<"Enter a string: "; cin >> str; //Reverse String for(int i=str.length()-1; i>=0; i--){ //If character is in upper case convert it to lower case if(str[i]>=65 && str[i]<=90) str[i] = str[i]+32; //assign the character to reverse string variable rev +=str[i]; } //Output result if(rev == str) cout << "Palindrome"; else cout << "Not Palindrome"; return 0; } |
Output:
Enter a string: momPalindrome
Strings such as Mom (first letter as upper case) do not match up with its reverse despite being a palindrome. So in the program, we lower the case of the characters before assigning them to the rev variable.
In this programming example, we learned to check a palindrome string in C++.