palindrome in c# ?

Question

well hi

I want to check weather the given string is palindrome or not .. i am getting ok for single word string like "sunus" but getting compile time errors while doing with big ones ? like "a but tuba" ??

Any solution manually appraoch plz

TY

Vulpes · Answer

Hemant and Sanjeeb See if your code can deal with this palindrome: Doc note: I dissent. A fast never prevents a fatness. I diet on cod. My previous version didn't deal with capitalization as I didn't think that was needed but I've adjusted it now so that it does again without using any string function: using System; using System.Text; class Test { static void Main() { string[] words = { sunus a but tuba Rotor raja Able was I ere I saw Elba vulpes Doc note: I dissent. A fast never prevents a fatness. I diet on cod. }; var sb = new StringBuilder(); for(int i = 0; i { // remove everything except letters from word foreach(char c in words[i]) { if (c >= 97 && c sb.Append(c); else if (c >= 65 && c sb.Append((char)(c + 32)); } string temp = sb.ToString(); sb.Length = 0; // now reverse the word for(int j = temp.Length - 1; j >= 0; j--) { sb.Append(temp[j]); } if (temp == sb.ToString()) { Console.WriteLine('{0}' is a palindrome words[i]); } else { Console.WriteLine('{0}' is not a palindrome words[i]); } sb.Length = 0; } Console.ReadKey(); } } However here's an improved way of doing it which doesn't reverse the string but iterates it from both ends at once comparing characters as it goes: using System; class Test { static void Main() { string[] words = { sunus a but tuba Rotor raja Able was I ere I saw Elba vulpes Doc note: I dissent. A fast never prevents a fatness. I diet on cod. Madam I'm Eve }; for(int i = 0; i { string w = words[i].ToLower(); bool isPalindrome = true; for(int j = 0 k = w.Length - 1; j { if (Char.IsLetter(w[j])) { if (char.IsLetter(w[k])) { if (w[j] != w[k]) { isPalindrome = false; break; } } else { j--; } } else if (char.IsLetter(w[k])) { k++; } } if (isPalindrome) { Console.WriteLine('{0}' is a palindrome words[i]); } else { Console.WriteLine('{0}' is not a palindrome words[i]); } } Console.ReadKey(); } }

Vulpes · Answer

Sunil Yes you can allow for capitalization in the way you suggested (i.e. using ToLower) but as I'd not used any functions in my original version I wanted to do the same in the updated version :) The Wikipedia article on palindromes is worth reading: http://en.wikipedia.org/wiki/Palindrome It has some more good examples such as: Eva can I stab bats in a cave? Rise to vote sir Dammit I'm mad!

SUNIL GUTTA · Answer

Ty very very much everyone :) got my thing Well but Sanjeeb Lenka your solution just superb but only thing is . It is applicable to single word strings but it will prove to be wrong while we consider  a but tuba  this one . I tried Hemant Srivastava well just awesome Ty but when pallamdrom contains non special chars(comma&# '...) like  a but tub'a  may fail TO every possible mistake . MR.Vulpes code mentioned above is best of sorts once check it TY very much for all ur whole hearted support to forum & people like me

Vulpes · Answer

Check my blog for a way of doing this using LINQ: http://www.c-sharpcorner.com/Blogs/8791/using-linq-to-check-whether-a-string-is-a-pangram-or-a-palin.aspx

Hemant Srivastava · Answer

Here is another way: private string CheckPalinDrome(string text) { //Converting into Upper case and remove blank spaces in between text = textBox2.Text.ToUpper().Replace(  string.Empty); string revText = ReverseString(text); if (revText == text) { return(palindrome); } else { return (Not palindrome); } } private string ReverseString(string s) { char[] arr = s.ToCharArray(); Array.Reverse(arr); return new string(arr); }

Sanjeeb Lenka · Answer

you can check this link for detail description. http://www.dotnetperls.com/stringcomparison

Sanjeeb Lenka · Answer

try this: using System; class Program { static void Main(string[] args) { string str revstr; Console.WriteLine(Enter Any String to Know It is Palindrome or not); str = Console.ReadLine(); char[] tempstr = str.ToCharArray(); Array.Reverse(tempstr); revstr = new string(tempstr); bool caseignore = str.Equals(revstr StringComparison.OrdinalIgnoreCase); if (caseignore == true) { Console.WriteLine(............ + str +  Is a Palindrome..........); } else { Console.WriteLine(............ + str +  Is Not a Palindrome........); } Console.Read(); } }

Vulpes · Answer

If by 'manually' you mean that you don't want to use any string functions then try this: using System; using System.Text; class Test { static void Main() { string[] words = { sunus a but tuba rotor raja able was I ere I saw elba vulpes }; // it's assumed words will always be lower case var sb = new StringBuilder(); for(int i = 0; i { // remove everything except letters from word foreach(char c in words[i]) { if (c >= 97 && c } string temp = sb.ToString(); sb.Length = 0; // now reverse the word for(int j = temp.Length - 1; j >= 0; j--) { sb.Append(temp[j]); } if (temp == sb.ToString()) { Console.WriteLine('{0}' is a palindrome words[i]); } else { Console.WriteLine('{0}' is not a palindrome words[i]); } sb.Length = 0; } Console.ReadKey(); } }

SUNIL GUTTA · Answer

yes its is useful :) i am done Well your above manual code is just fantastic :) just felt the taste of programming language its gives :) Ty Vulpes & everyone for support

SUNIL GUTTA · Answer

Hemant Srivastava & Sanjeeb Lenka ty again friends for re-replying Well this is i have this simple string like  PL-ATITAL P  saying it as not a pallondrome but thing we we all know it is ... + acc to the methods provided by respectively the output will be wen we reverse like PLATITA-LP which is not equal to PL-ATITALP beocz of that ' - ' ... please once can you cross check with the given string and ping back :) ty ty thank you :)

SUNIL GUTTA · Answer

My previous version didn't deal with capitalization ??? I think it can be done with small modification in your Foreach loop i.e foreach(char c in words[i]) when i changed ur foreach loop into something like this its working good for everything ..!! -------------------- foreach(char c in words[i].ToLower())----------------- I this this can be done right vulpes :)

Sanjeeb Lenka · Answer

my code is also working with any string and special character i checked .

Hemant Srivastava · Answer

Hi Sunil just clarifying your doubt:  Hemant Srivastava well just awesome Ty but when pallamdrom contains non special chars(comma&# '...) like  a but tub'a  may fail The code which I provided would work with special characters too..

SUNIL GUTTA · Answer

If by 'manually' ?? well vulpes can this code done in small way using whatever functions in c# ?? Sanjeeb Lenka ty for your reply to :) its way to complex to understand for a guy like me StringComparison.OrdinalIgnoreCase ??? please can u tell me what is it work & ty friend