Bdtjtk

Question

I have a string as input and have to break the string in two substrings. If the left substring equals the right substring then do some logic.

How can I do this?

Sample:

public bool getStatus(string myString)

{



}

Example: myString = "ankYkna", so if we break it into two substring it would be:
left-part = "ank",
right-part = "ank" (after reversal).

What's your actual problem here? Just use myString.SubString(). — Mar 20 '12 at 16:23

AustinWBryan 2,35121332 · Accepted Answer · 2018-07-17 22:33:21Z

21

public static bool getStatus(string myString)

{

    string first = myString.Substring(0, myString.Length / 2);

    char arr   = myString.ToCharArray();



    Array.Reverse(arr);



    string temp   = new string(arr);

    string second = temp.Substring(0, temp.Length / 2);



    return first.Equals(second);

}

edited Jul 17 '18 at 22:33

AustinWBryan

2,35121332

answered Mar 20 '12 at 16:31

ionden

10.4k13333

This actually will not work for palindromes with punctuation and asymetrical whitespace. Example: "No 'X' in Nixon." Is a palindrome.

– Espen
Nov 18 '16 at 10:15

add a comment |

Balazs TihanyiBalazs Tihanyi 5,30441622 · Accepted Answer · 2012-03-20 18:21:36Z

59

Just for fun:

return myString.SequenceEqual(myString.Reverse());

answered Mar 20 '12 at 18:21

Balazs Tihanyi

5,30441622

1

Missing using System.Linq;

– Junior M
Apr 11 '17 at 20:43

add a comment |

Balazs TihanyiBalazs Tihanyi 5,30441622 · Accepted Answer · 2012-03-20 16:35:28Z

12

int length = myString.Length;

for (int i = 0; i < length / 2; i++)

{

    if (myString[i] != myString[length - i - 1])

        return false;

}

return true;

answered Mar 20 '12 at 16:35

Balazs Tihanyi

5,30441622

Short and concise. My compliments.

– M. Mimpen
May 22 '15 at 14:23

Marginally quicker would be to save the length / 2 within its own variable.

– krillgar
Feb 12 '16 at 18:24

add a comment |

score 12 · Accepted Answer · 2016-02-12 19:46:08Z

12

Using LINQ and off course far from the best solution

var original = "ankYkna";

var reversed = new string(original.Reverse().ToArray());

var palindrom = original == reversed;

edited Feb 12 '16 at 19:46

answered Mar 20 '12 at 16:37

Adrian Iftode

13.5k23565

A string is inherently a character array, so the .ToCharArray() call is redundant.

– krillgar
Feb 12 '16 at 18:23

@krillgar you're right, string implements IEnumerable<char> so the ToCharArray is not needed. I can't tell if it was like this back in 2012.

– Adrian Iftode
Feb 12 '16 at 19:45

2

I am pretty sure it was always the case, but people were so explicit when LINQ first came out. I just stumbled across this question and wanted to point that out to anyone else who came across your solid answer.

– krillgar
Feb 12 '16 at 19:47

1

for case sensitivity do add String.Equals(word,original,StringComparison.OrdinalIgnoreCase)

– afr0
Jun 14 '17 at 13:46

add a comment |

Adrian Iftode 13.5k23565 · Accepted Answer · 2016-10-28 11:33:58Z

 public static bool IsPalindrome(string value)

        {

            int i = 0;

            int j = value.Length - 1;

            while (true)

            {

                if (i > j)

                {

                    return true;

                }

                char a = value[i];

                char b = value[j];

                if (char.ToLower(a) != char.ToLower(b))

                {

                    return false;

                }

                i++;

                j--;

            }

        }

fubo 29.8k967104 · Accepted Answer · 2018-05-17 09:50:42Z

3

A single line of code using Linq

public static bool IsPalindrome(string str)  

{

    return str.SequenceEqual(str.Reverse());

}

edited May 17 '18 at 9:50

fubo

29.8k967104

answered Dec 16 '12 at 3:01

Ernesto Cejas

764

add a comment |

score 2 · Accepted Answer · 2013-07-20 20:57:12Z

//This c# method will check for even and odd lengh palindrome string

public static bool IsPalenDrome(string palendromeString)

        {

            bool isPalenDrome = false;



            try

            {

                int halfLength = palendromeString.Length / 2;



                string leftHalfString = palendromeString.Substring(0,halfLength);



                char reversedArray = palendromeString.ToCharArray();

                Array.Reverse(reversedArray);

                string reversedString = new string(reversedArray);



                string rightHalfStringReversed = reversedString.Substring(0, halfLength);



                isPalenDrome = leftHalfString == rightHalfStringReversed ? true : false;

            }

            catch (Exception ex)

            {

                throw ex;

            }



            return isPalenDrome;

        }

LshakaLshaka 352 · Accepted Answer · 2014-06-11 15:49:21Z

1

This way is both concise in appearance & processes very quickly.

Func<string, bool> IsPalindrome = s => s.Reverse().Equals(s);

answered Jun 11 '14 at 15:49

Lshaka

352

3

It's also dead wrong, since it will always return false. s.Reverse() is an IEnumerable<char>, which never compares reference-equal to the original String (assuming the standard definition of Enumerable.Reverse and Object.Equals).

– Jeroen Mostert
Apr 13 '17 at 12:01

add a comment |

score 1 · Accepted Answer · 2017-05-10 00:20:16Z

1

String extension method, easy to use:

    public static bool IsPalindrome(this string str)

    {

        str = new Regex("[^a-zA-Z]").Replace(str, "").ToLower();

        return !str.Where((t, i) => t != str[str.Length - i - 1]).Any();

    }

edited May 10 '17 at 0:20

answered Aug 26 '16 at 22:59

Dr3

114

add a comment |

score 1 · Accepted Answer · 2017-07-12 07:47:50Z

 private void CheckIfPalindrome(string str) 

        {

            //place string in array of chars

            char array = str.ToCharArray(); 

            int length = array.Length -1 ;

            Boolean palindrome =true;

            for (int i = 0; i <= length; i++)//go through the array

            {

                if (array[i] != array[length])//compare if the char in the same positions are the same eg "tattarrattat" will compare array[0]=t with array[11] =t if are not the same stop the for loop

                {

                    MessageBox.Show("not");

                    palindrome = false;

                    break;



                }

                else //if they are the same make length smaller by one and do the same 

                {                   

                  length--;

                }



            }

            if (palindrome) MessageBox.Show("Palindrome"); 



        }

Code only answers arent encouraged as they dont provide much information for future readers — Jul 11 '17 at 13:45
I have an explanation in the comment area what else should i explain? — Mar 8 '18 at 11:35

Thomas LevesqueThomas Levesque 236k53494665 · Accepted Answer · 2012-03-20 16:30:23Z

0

If you just need to detect a palindrome, you can do it with a regex, as explained here. Probably not the most efficient approach, though...

answered Mar 20 '12 at 16:30

Thomas Levesque

236k53494665

add a comment |

T. KileyT. Kiley 2,3621427 · Accepted Answer · 2012-03-20 16:33:15Z

That is non-trivial, there is no built in method to do that for you, you'll have to write your own. You will need to consider what rules you would like to check, like you implicitly stated you accepted reversing of one string. Also, you missed out the middle character, is this only if odd length?

So you will have something like:

if(myString.length % 2 = 0)

{

     //even

     string a = myString.substring(0, myString.length / 2);

     string b = myString.substring(myString.length / 2 + 1, myString.lenght/2);



     if(a == b)

           return true;



     //Rule 1: reverse

     if(a == b.reverse()) //can't remember if this is a method, if not you'll have to write that too

           return true;

etc, also doing whatever you want for odd strings

Lee Taylor 5,03472442 · Accepted Answer · 2013-07-20 22:12:43Z

This C# method will check for even and odd length palindrome string (Recursive Approach):

public static bool IsPalindromeResursive(int rightIndex, int leftIndex, char inputString)

{

    if (rightIndex == leftIndex || rightIndex < leftIndex)

        return true;

    if (inputString[rightIndex] == inputString[leftIndex])

        return IsPalindromeResursive(--rightIndex, ++leftIndex, inputString);

    else

        return false;            

}

kennydustkennydust 8701114 · Accepted Answer · 2014-04-23 05:11:19Z

0

public Boolean IsPalindrome(string value)

{

   var one = value.ToList<char>();

   var two = one.Reverse<char>().ToList();

   return one.Equals(two);

}

answered Apr 23 '14 at 5:11

kennydust

8701114

add a comment |

Omer KOmer K 2,98474566 · Accepted Answer · 2014-04-23 11:16:11Z

protected bool CheckIfPalindrome(string text)

{

    if (text != null)

    {

        string strToUpper = Text.ToUpper();

        char toReverse = strToUpper.ToCharArray();

        Array.Reverse(toReverse );

        String strReverse = new String(toReverse);

        if (strToUpper == toReverse)

        {

            return true;

        }

        else

        {

            return false;

        }

    }

    else

    {

        return false;

    }

}

Use this the sipmlest way.

cannot compare string to char

– wruckie
Jan 13 '15 at 0:37 — Jan 13 '15 at 0:37

jeetendra singh negijeetendra singh negi 1 · Accepted Answer · 2014-09-13 08:07:22Z

class Program

{

    static void Main(string args)

    {



        string s, revs = "";

        Console.WriteLine(" Enter string");

        s = Console.ReadLine();

        for (int i = s.Length - 1; i >= 0; i--) //String Reverse

        {

            Console.WriteLine(i);

            revs += s[i].ToString();

        }

        if (revs == s) // Checking whether string is palindrome or not

        {

            Console.WriteLine("String is Palindrome");

        }

        else

        {

            Console.WriteLine("String is not Palindrome");

        }

        Console.ReadKey();

    }

}

M. MimpenM. Mimpen 9091121 · Accepted Answer · 2015-05-22 14:18:13Z

public bool IsPalindroom(string input)

{

    input = input.ToLower();

    var loops = input.Length / 2;

    var higherBoundIdx = input.Length - 1;

    for (var lowerBoundIdx = 0; lowerBoundIdx < loops; lowerBoundIdx++, higherBoundIdx--)

    {

        if (input[lowerBoundIdx] != input[higherBoundIdx])

        return false;

    }

    return true;

}

Rennish JosephRennish Joseph 3461520 · Accepted Answer · 2016-02-14 17:44:05Z

public static  bool IsPalindrome(string word)

        {

            //first reverse the string

            string reversedString = new string(word.Reverse().ToArray());

            return string.Compare(word, reversedString) == 0 ? true : false;

        }

Vishav PremlallVishav Premlall 6312 · Accepted Answer · 2016-10-20 06:15:33Z

Here is an absolutely simple way to do this,

Receive the word as input into a method.

Assign a temp variable to the original value.

Loop through the initial word, and add the last character to the reversal that you are constructing until the inital word has no more characters.

Now use the spare you created to hold the original value to compare to the constructed copy.

This is a nice way as u don't have to cast ints and doubles. U can just pass them to the method in their string representation by using the ToString() method.

public static bool IsPalindrome(string word)

    {

        string spare = word;

        string reversal = null;

        while (word.Length > 0)

        {

            reversal = string.Concat(reversal, word.LastOrDefault());

            word = word.Remove(word.Length - 1);

        }

        return spare.Equals(reversal);

    }

So from your main method,
For even and odd length strings u just pass the whole string into the method.

SaketSaket 1,40221134 · Accepted Answer · 2016-10-20 07:31:56Z

0

Out of all the solutions, below can also be tried:

public static bool IsPalindrome(string s)

{

    return s == new string(s.Reverse().ToArray());

}

answered Oct 20 '16 at 7:31

Saket

1,40221134

add a comment |

score 0 · Accepted Answer · 2016-10-24 20:07:06Z

Since a palindrome also includes numbers, words, sentences, and any combinations of these, and should ignore punctuation and case, (See Wikipedia Article)
I propose this solution:

public class Palindrome

{

    static IList<int> Allowed = new List<int> {

        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'h',

        'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',

        'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',

        '1', '2', '3', '4', '5', '6', '7', '8', '9',

        '0'

    };

    private static int GetJustAllowed(string text)

    {

        List<int> characters = new List<int>();

        foreach (var c in text)

             characters.Add(c | 0x20); 



        return characters.Where(c => Allowed.Contains(c)).ToArray();

    }

    public static bool IsPalindrome(string text)

    {

        if(text == null || text.Length == 1)

             return true;



        int chars = GetJustAllowed(text);

        var length = chars.Length;



        while (length > 0)

            if (chars[chars.Length - length] != chars[--length])

                return false;



        return true;

    }

    public static bool IsPalindrome(int number)

    {

        return IsPalindrome(number.ToString());

    }

    public static bool IsPalindrome(double number)

    {

        return IsPalindrome(number.ToString());

    }

    public static bool IsPalindrome(decimal number)

    {

        return IsPalindrome(number.ToString());

    }



}

The allowed list should certainly be extended to include more languages and concepts than just English, but I hope to illustrate that just checking if string.reverse() == string is not a complete solution to the palindrome problem. — Oct 24 '16 at 20:05

smottt 2,72373039 · Accepted Answer · 2017-01-18 13:04:50Z

static void Main(string args)

{

    string str, rev="";



    Console.Write("Enter string");



    str = Console.ReadLine();



    for (int i = str.Length - 1; i >= 0; i--)

    {

        rev = rev + str[i];

    }



    if (rev == str)

        Console.Write("Entered string is pallindrome");

    else

        Console.Write("Entered string is not pallindrome");



    Console.ReadKey();

}

user3725809user3725809 11 · Accepted Answer · 2017-09-13 00:10:01Z

string test = "Malayalam";

            char palindrome = test.ToCharArray();

            char reversestring = new char[palindrome.Count()];

            for (int i = palindrome.Count() - 1; i >= 0; i--)

            {

                reversestring[palindrome.Count() - 1 - i] = palindrome[i];



            }



            string materializedString = new string(reversestring);



            if (materializedString.ToLower() == test.ToLower())

            {

                Console.Write("Palindrome!");

            }

            else

            {

                Console.Write("Not a Palindrome!");

            }



            Console.Read();

Artyom ArshakyanArtyom Arshakyan 11 · Accepted Answer · 2017-11-04 09:23:41Z

0

public static bool palindrome(string t)

    {

        int i = t.Length;

        for (int j = 0; j < i / 2; j++)

        {

            if (t[j] == t[i - j-1])

            {

                continue;

            }

            else

            {

                return false;

                break;

            }

        }

        return true;

    }

answered Nov 4 '17 at 9:23

Artyom Arshakyan

11

1

Please, next time, along with the code enter a short explanation.

– Kerberos
Nov 4 '17 at 9:36

add a comment |

score 0 · Accepted Answer · 2017-12-22 13:02:24Z

use this way from dotnetperls

  using System;



    class Program

    {

        /// <summary>

        /// Determines whether the string is a palindrome.

        /// </summary>

        public static bool IsPalindrome(string value)

        {

            int min = 0;

            int max = value.Length - 1;

            while (true)

            {

                if (min > max)

                {

                    return true;

                }

                char a = value[min];

                char b = value[max];



                // Scan forward for a while invalid.

                while (!char.IsLetterOrDigit(a))

                {

                    min++;

                    if (min > max)

                    {

                        return true;

                    }

                    a = value[min];

                }



                // Scan backward for b while invalid.

                while (!char.IsLetterOrDigit(b))

                {

                    max--;

                    if (min > max)

                    {

                        return true;

                    }

                    b = value[max];

                }



                if (char.ToLower(a) != char.ToLower(b))

                {

                    return false;

                }

                min++;

                max--;

            }

        }



        static void Main()

        {

            string array =

            {

                "A man, a plan, a canal: Panama.",

                "A Toyota. Race fast, safe car. A Toyota.",

                "Cigar? Toss it in a can. It is so tragic.",

                "Dammit, I'm mad!",

                "Delia saw I was ailed.",

                "Desserts, I stressed!",

                "Draw, O coward!",

                "Lepers repel.",

                "Live not on evil.",

                "Lonely Tylenol.",

                "Murder for a jar of red rum.",

                "Never odd or even.",

                "No lemon, no melon.",

                "Senile felines.",

                "So many dynamos!",

                "Step on no pets.",

                "Was it a car or a cat I saw?",



                "Dot Net Perls is not a palindrome.",

                "Why are you reading this?",

                "This article is not useful.",

                "...",

                "...Test"

            };



            foreach (string value in array)

            {

                Console.WriteLine("{0} = {1}", value, IsPalindrome(value));

            }

        }

    }

Please add description to your code explaining what it does

– Rahul Gupta
Dec 22 '17 at 11:28 — Dec 22 '17 at 11:28
see the comment at the top of IsPalindrome function :)

– FAREH
Dec 22 '17 at 13:05 — Dec 22 '17 at 13:05

Kzrystof 2,00431321 · Accepted Answer · 2018-07-17 20:45:19Z

This is a short and efficient way of checking palindrome.

bool checkPalindrome(string inputString) {



    int length = inputString.Length;

    for(int i = 0; i < length/2; i++){

        if(inputString[i] != inputString[length-1-i]){

            return false;

        }

    }



    return true;



}

Tanvir AnowarTanvir Anowar 456 · Accepted Answer · 2018-08-07 19:39:14Z

public bool Solution(string content)

    {

        int length = content.Length;



        int half = length/2;



        int isOddLength = length%2;



        // Counter for checking the string from the middle 

        int j = (isOddLength==0) ? half:half+1;



        for(int i=half-1;i>=0;i--)

        {                

            if(content[i] != content[j])

            {

               return false;

            }

            j++;



        }

        return true;

    }

Bonus points if you add some details on how this works for future visitors. A couple of test cases, too, maybe? — Aug 7 '18 at 20:08

Jerko ViskovJerko Viskov 1 · Accepted Answer · 2019-01-30 17:47:22Z

    public  bool MojTestPalindrome (string word)

    {

        bool yes = false;



        chartest1 = word.ToArray();

        char test2 = test1.Reverse().ToArray();

        for (int i=0; i< test2.Length; i++)

        {



            if (test1[i] != test2[test2.Length - 1 - i])

            {



                yes = false;

                break;



            }

            else {   

                yes = true;





            }

        }

        if (yes == true)

        {

            return true;

        }

        else



            return false;                

    }

score -1 · Accepted Answer · 2018-01-11 08:04:24Z

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;





class palindrome

{

    static void Main(string args)

    {

        Console.Write("Enter a number:");

        string panstring = Console.ReadLine();

        Palindrome(panstring);

        Console.ReadKey();

    }

     static int index = 0;

     public static void Palindrome(string strexcluding)

    {

        try

        {

            string reversecounter = string.Empty;



            for (int i = strexcluding.Length - 1; i >= 0; i--)

            {

                if (strexcluding[i].ToString() != null)

                    reversecounter += strexcluding[i].ToString();

            }

            if (reversecounter == strexcluding)

            {

                Console.WriteLine("Palindrome Number: " + strexcluding);

            }

            else

            {

                Sum(strexcluding);

            }

        }

         catch(Exception ex)

        {

            Console.WriteLine(ex.ToString());

        }

    }



    public static void Sum(string stringnumber)

    {

        try

        {

            index++;

            string number1 = stringnumber;

            string number2 = stringnumber;

            string array = new string[number1.Length];

            string obtained = string.Empty;

            string sreverse = null;



            Console.WriteLine(index + ".step : " + number1 + "+" + number2);



            for (int i = 0; i < number1.Length; i++)

            {

                int temp1 = Convert.ToInt32(number1[number1.Length - i - 1].ToString());

                int temp2 = Convert.ToInt32(number2[number2.Length - i - 1].ToString());



                if (temp1 + temp2 >= 10)

                {

                    if (number1.Length - 1 == number1.Length - 1 - i)

                    {

                        array[i] = ((temp1 + temp2) - 10).ToString();

                        obtained = "one";

                    }

                    else if (number1.Length - 1 == i)

                    {

                        if (obtained == "one")

                        {

                            array[i] = (temp1 + temp2 + 1).ToString();

                        }

                        else

                        {

                            array[i] = (temp1 + temp2).ToString();

                        }

                    }

                    else

                    {

                        if (obtained == "one")

                        {

                            array[i] = ((temp1 + temp2 + 1) - 10).ToString();

                        }

                        else

                        {

                            array[i] = ((temp1 + temp2) - 10).ToString();

                            obtained = "one";

                        }



                    }

                }



                else

                {

                    if (obtained == "one")

                        array[i] = (temp1 + temp2 + 1).ToString();

                    else

                        array[i] = (temp1 + temp2).ToString();

                    obtained = "Zero";

                }



            }



            for (int i = array.Length - 1; i >= 0; i--)

            {

                if (array[i] != null)

                    sreverse += array[i].ToString();

            }



            Palindrome(sreverse);

        }

        catch(Exception ex)

        {

            Console.WriteLine(ex.ToString());

        }

    }

}

AustinWBryan 2,35121332 · Accepted Answer · 2018-07-17 22:33:21Z

21

public static bool getStatus(string myString)

{

    string first = myString.Substring(0, myString.Length / 2);

    char arr   = myString.ToCharArray();



    Array.Reverse(arr);



    string temp   = new string(arr);

    string second = temp.Substring(0, temp.Length / 2);



    return first.Equals(second);

}

edited Jul 17 '18 at 22:33

AustinWBryan

2,35121332

answered Mar 20 '12 at 16:31

ionden

10.4k13333

This actually will not work for palindromes with punctuation and asymetrical whitespace. Example: "No 'X' in Nixon." Is a palindrome.

– Espen
Nov 18 '16 at 10:15

add a comment |

Balazs TihanyiBalazs Tihanyi 5,30441622 · Accepted Answer · 2012-03-20 18:21:36Z

59

Just for fun:

return myString.SequenceEqual(myString.Reverse());

answered Mar 20 '12 at 18:21

Balazs Tihanyi

5,30441622

1

Missing using System.Linq;

– Junior M
Apr 11 '17 at 20:43

add a comment |

Balazs TihanyiBalazs Tihanyi 5,30441622 · Accepted Answer · 2012-03-20 16:35:28Z

12

int length = myString.Length;

for (int i = 0; i < length / 2; i++)

{

    if (myString[i] != myString[length - i - 1])

        return false;

}

return true;

answered Mar 20 '12 at 16:35

Balazs Tihanyi

5,30441622

Short and concise. My compliments.

– M. Mimpen
May 22 '15 at 14:23

Marginally quicker would be to save the length / 2 within its own variable.

– krillgar
Feb 12 '16 at 18:24

add a comment |

score 12 · Accepted Answer · 2016-02-12 19:46:08Z

12

Using LINQ and off course far from the best solution

var original = "ankYkna";

var reversed = new string(original.Reverse().ToArray());

var palindrom = original == reversed;

edited Feb 12 '16 at 19:46

answered Mar 20 '12 at 16:37

Adrian Iftode

13.5k23565

A string is inherently a character array, so the .ToCharArray() call is redundant.

– krillgar
Feb 12 '16 at 18:23

@krillgar you're right, string implements IEnumerable<char> so the ToCharArray is not needed. I can't tell if it was like this back in 2012.

– Adrian Iftode
Feb 12 '16 at 19:45

2

I am pretty sure it was always the case, but people were so explicit when LINQ first came out. I just stumbled across this question and wanted to point that out to anyone else who came across your solid answer.

– krillgar
Feb 12 '16 at 19:47

1

for case sensitivity do add String.Equals(word,original,StringComparison.OrdinalIgnoreCase)

– afr0
Jun 14 '17 at 13:46

add a comment |

Adrian Iftode 13.5k23565 · Accepted Answer · 2016-10-28 11:33:58Z

 public static bool IsPalindrome(string value)

        {

            int i = 0;

            int j = value.Length - 1;

            while (true)

            {

                if (i > j)

                {

                    return true;

                }

                char a = value[i];

                char b = value[j];

                if (char.ToLower(a) != char.ToLower(b))

                {

                    return false;

                }

                i++;

                j--;

            }

        }

fubo 29.8k967104 · Accepted Answer · 2018-05-17 09:50:42Z

3

A single line of code using Linq

public static bool IsPalindrome(string str)  

{

    return str.SequenceEqual(str.Reverse());

}

edited May 17 '18 at 9:50

fubo

29.8k967104

answered Dec 16 '12 at 3:01

Ernesto Cejas

764

add a comment |

score 2 · Accepted Answer · 2013-07-20 20:57:12Z

//This c# method will check for even and odd lengh palindrome string

public static bool IsPalenDrome(string palendromeString)

        {

            bool isPalenDrome = false;



            try

            {

                int halfLength = palendromeString.Length / 2;



                string leftHalfString = palendromeString.Substring(0,halfLength);



                char reversedArray = palendromeString.ToCharArray();

                Array.Reverse(reversedArray);

                string reversedString = new string(reversedArray);



                string rightHalfStringReversed = reversedString.Substring(0, halfLength);



                isPalenDrome = leftHalfString == rightHalfStringReversed ? true : false;

            }

            catch (Exception ex)

            {

                throw ex;

            }



            return isPalenDrome;

        }

LshakaLshaka 352 · Accepted Answer · 2014-06-11 15:49:21Z

1

This way is both concise in appearance & processes very quickly.

Func<string, bool> IsPalindrome = s => s.Reverse().Equals(s);

answered Jun 11 '14 at 15:49

Lshaka

352

3

It's also dead wrong, since it will always return false. s.Reverse() is an IEnumerable<char>, which never compares reference-equal to the original String (assuming the standard definition of Enumerable.Reverse and Object.Equals).

– Jeroen Mostert
Apr 13 '17 at 12:01

add a comment |

score 1 · Accepted Answer · 2017-05-10 00:20:16Z

1

String extension method, easy to use:

    public static bool IsPalindrome(this string str)

    {

        str = new Regex("[^a-zA-Z]").Replace(str, "").ToLower();

        return !str.Where((t, i) => t != str[str.Length - i - 1]).Any();

    }

edited May 10 '17 at 0:20

answered Aug 26 '16 at 22:59

Dr3

114

add a comment |

score 1 · Accepted Answer · 2017-07-12 07:47:50Z

 private void CheckIfPalindrome(string str) 

        {

            //place string in array of chars

            char array = str.ToCharArray(); 

            int length = array.Length -1 ;

            Boolean palindrome =true;

            for (int i = 0; i <= length; i++)//go through the array

            {

                if (array[i] != array[length])//compare if the char in the same positions are the same eg "tattarrattat" will compare array[0]=t with array[11] =t if are not the same stop the for loop

                {

                    MessageBox.Show("not");

                    palindrome = false;

                    break;



                }

                else //if they are the same make length smaller by one and do the same 

                {                   

                  length--;

                }



            }

            if (palindrome) MessageBox.Show("Palindrome"); 



        }

Code only answers arent encouraged as they dont provide much information for future readers — Jul 11 '17 at 13:45
I have an explanation in the comment area what else should i explain? — Mar 8 '18 at 11:35

Thomas LevesqueThomas Levesque 236k53494665 · Accepted Answer · 2012-03-20 16:30:23Z

0

If you just need to detect a palindrome, you can do it with a regex, as explained here. Probably not the most efficient approach, though...

answered Mar 20 '12 at 16:30

Thomas Levesque

236k53494665

add a comment |

T. KileyT. Kiley 2,3621427 · Accepted Answer · 2012-03-20 16:33:15Z

That is non-trivial, there is no built in method to do that for you, you'll have to write your own. You will need to consider what rules you would like to check, like you implicitly stated you accepted reversing of one string. Also, you missed out the middle character, is this only if odd length?

So you will have something like:

if(myString.length % 2 = 0)

{

     //even

     string a = myString.substring(0, myString.length / 2);

     string b = myString.substring(myString.length / 2 + 1, myString.lenght/2);



     if(a == b)

           return true;



     //Rule 1: reverse

     if(a == b.reverse()) //can't remember if this is a method, if not you'll have to write that too

           return true;

etc, also doing whatever you want for odd strings

Lee Taylor 5,03472442 · Accepted Answer · 2013-07-20 22:12:43Z

This C# method will check for even and odd length palindrome string (Recursive Approach):

public static bool IsPalindromeResursive(int rightIndex, int leftIndex, char inputString)

{

    if (rightIndex == leftIndex || rightIndex < leftIndex)

        return true;

    if (inputString[rightIndex] == inputString[leftIndex])

        return IsPalindromeResursive(--rightIndex, ++leftIndex, inputString);

    else

        return false;            

}

kennydustkennydust 8701114 · Accepted Answer · 2014-04-23 05:11:19Z

0

public Boolean IsPalindrome(string value)

{

   var one = value.ToList<char>();

   var two = one.Reverse<char>().ToList();

   return one.Equals(two);

}

answered Apr 23 '14 at 5:11

kennydust

8701114

add a comment |

Omer KOmer K 2,98474566 · Accepted Answer · 2014-04-23 11:16:11Z

protected bool CheckIfPalindrome(string text)

{

    if (text != null)

    {

        string strToUpper = Text.ToUpper();

        char toReverse = strToUpper.ToCharArray();

        Array.Reverse(toReverse );

        String strReverse = new String(toReverse);

        if (strToUpper == toReverse)

        {

            return true;

        }

        else

        {

            return false;

        }

    }

    else

    {

        return false;

    }

}

Use this the sipmlest way.

cannot compare string to char

– wruckie
Jan 13 '15 at 0:37 — Jan 13 '15 at 0:37

jeetendra singh negijeetendra singh negi 1 · Accepted Answer · 2014-09-13 08:07:22Z

class Program

{

    static void Main(string args)

    {



        string s, revs = "";

        Console.WriteLine(" Enter string");

        s = Console.ReadLine();

        for (int i = s.Length - 1; i >= 0; i--) //String Reverse

        {

            Console.WriteLine(i);

            revs += s[i].ToString();

        }

        if (revs == s) // Checking whether string is palindrome or not

        {

            Console.WriteLine("String is Palindrome");

        }

        else

        {

            Console.WriteLine("String is not Palindrome");

        }

        Console.ReadKey();

    }

}

M. MimpenM. Mimpen 9091121 · Accepted Answer · 2015-05-22 14:18:13Z

public bool IsPalindroom(string input)

{

    input = input.ToLower();

    var loops = input.Length / 2;

    var higherBoundIdx = input.Length - 1;

    for (var lowerBoundIdx = 0; lowerBoundIdx < loops; lowerBoundIdx++, higherBoundIdx--)

    {

        if (input[lowerBoundIdx] != input[higherBoundIdx])

        return false;

    }

    return true;

}

Rennish JosephRennish Joseph 3461520 · Accepted Answer · 2016-02-14 17:44:05Z

public static  bool IsPalindrome(string word)

        {

            //first reverse the string

            string reversedString = new string(word.Reverse().ToArray());

            return string.Compare(word, reversedString) == 0 ? true : false;

        }

Vishav PremlallVishav Premlall 6312 · Accepted Answer · 2016-10-20 06:15:33Z

Here is an absolutely simple way to do this,

Receive the word as input into a method.

Assign a temp variable to the original value.

Loop through the initial word, and add the last character to the reversal that you are constructing until the inital word has no more characters.

Now use the spare you created to hold the original value to compare to the constructed copy.

This is a nice way as u don't have to cast ints and doubles. U can just pass them to the method in their string representation by using the ToString() method.

public static bool IsPalindrome(string word)

    {

        string spare = word;

        string reversal = null;

        while (word.Length > 0)

        {

            reversal = string.Concat(reversal, word.LastOrDefault());

            word = word.Remove(word.Length - 1);

        }

        return spare.Equals(reversal);

    }

So from your main method,
For even and odd length strings u just pass the whole string into the method.

SaketSaket 1,40221134 · Accepted Answer · 2016-10-20 07:31:56Z

0

Out of all the solutions, below can also be tried:

public static bool IsPalindrome(string s)

{

    return s == new string(s.Reverse().ToArray());

}

answered Oct 20 '16 at 7:31

Saket

1,40221134

add a comment |

score 0 · Accepted Answer · 2016-10-24 20:07:06Z

Since a palindrome also includes numbers, words, sentences, and any combinations of these, and should ignore punctuation and case, (See Wikipedia Article)
I propose this solution:

public class Palindrome

{

    static IList<int> Allowed = new List<int> {

        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'h',

        'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',

        'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',

        '1', '2', '3', '4', '5', '6', '7', '8', '9',

        '0'

    };

    private static int GetJustAllowed(string text)

    {

        List<int> characters = new List<int>();

        foreach (var c in text)

             characters.Add(c | 0x20); 



        return characters.Where(c => Allowed.Contains(c)).ToArray();

    }

    public static bool IsPalindrome(string text)

    {

        if(text == null || text.Length == 1)

             return true;



        int chars = GetJustAllowed(text);

        var length = chars.Length;



        while (length > 0)

            if (chars[chars.Length - length] != chars[--length])

                return false;



        return true;

    }

    public static bool IsPalindrome(int number)

    {

        return IsPalindrome(number.ToString());

    }

    public static bool IsPalindrome(double number)

    {

        return IsPalindrome(number.ToString());

    }

    public static bool IsPalindrome(decimal number)

    {

        return IsPalindrome(number.ToString());

    }



}

The allowed list should certainly be extended to include more languages and concepts than just English, but I hope to illustrate that just checking if string.reverse() == string is not a complete solution to the palindrome problem. — Oct 24 '16 at 20:05

smottt 2,72373039 · Accepted Answer · 2017-01-18 13:04:50Z

static void Main(string args)

{

    string str, rev="";



    Console.Write("Enter string");



    str = Console.ReadLine();



    for (int i = str.Length - 1; i >= 0; i--)

    {

        rev = rev + str[i];

    }



    if (rev == str)

        Console.Write("Entered string is pallindrome");

    else

        Console.Write("Entered string is not pallindrome");



    Console.ReadKey();

}

user3725809user3725809 11 · Accepted Answer · 2017-09-13 00:10:01Z

string test = "Malayalam";

            char palindrome = test.ToCharArray();

            char reversestring = new char[palindrome.Count()];

            for (int i = palindrome.Count() - 1; i >= 0; i--)

            {

                reversestring[palindrome.Count() - 1 - i] = palindrome[i];



            }



            string materializedString = new string(reversestring);



            if (materializedString.ToLower() == test.ToLower())

            {

                Console.Write("Palindrome!");

            }

            else

            {

                Console.Write("Not a Palindrome!");

            }



            Console.Read();

Artyom ArshakyanArtyom Arshakyan 11 · Accepted Answer · 2017-11-04 09:23:41Z

0

public static bool palindrome(string t)

    {

        int i = t.Length;

        for (int j = 0; j < i / 2; j++)

        {

            if (t[j] == t[i - j-1])

            {

                continue;

            }

            else

            {

                return false;

                break;

            }

        }

        return true;

    }

answered Nov 4 '17 at 9:23

Artyom Arshakyan

11

1

Please, next time, along with the code enter a short explanation.

– Kerberos
Nov 4 '17 at 9:36

add a comment |

score 0 · Accepted Answer · 2017-12-22 13:02:24Z

use this way from dotnetperls

  using System;



    class Program

    {

        /// <summary>

        /// Determines whether the string is a palindrome.

        /// </summary>

        public static bool IsPalindrome(string value)

        {

            int min = 0;

            int max = value.Length - 1;

            while (true)

            {

                if (min > max)

                {

                    return true;

                }

                char a = value[min];

                char b = value[max];



                // Scan forward for a while invalid.

                while (!char.IsLetterOrDigit(a))

                {

                    min++;

                    if (min > max)

                    {

                        return true;

                    }

                    a = value[min];

                }



                // Scan backward for b while invalid.

                while (!char.IsLetterOrDigit(b))

                {

                    max--;

                    if (min > max)

                    {

                        return true;

                    }

                    b = value[max];

                }



                if (char.ToLower(a) != char.ToLower(b))

                {

                    return false;

                }

                min++;

                max--;

            }

        }



        static void Main()

        {

            string array =

            {

                "A man, a plan, a canal: Panama.",

                "A Toyota. Race fast, safe car. A Toyota.",

                "Cigar? Toss it in a can. It is so tragic.",

                "Dammit, I'm mad!",

                "Delia saw I was ailed.",

                "Desserts, I stressed!",

                "Draw, O coward!",

                "Lepers repel.",

                "Live not on evil.",

                "Lonely Tylenol.",

                "Murder for a jar of red rum.",

                "Never odd or even.",

                "No lemon, no melon.",

                "Senile felines.",

                "So many dynamos!",

                "Step on no pets.",

                "Was it a car or a cat I saw?",



                "Dot Net Perls is not a palindrome.",

                "Why are you reading this?",

                "This article is not useful.",

                "...",

                "...Test"

            };



            foreach (string value in array)

            {

                Console.WriteLine("{0} = {1}", value, IsPalindrome(value));

            }

        }

    }

Please add description to your code explaining what it does

– Rahul Gupta
Dec 22 '17 at 11:28 — Dec 22 '17 at 11:28
see the comment at the top of IsPalindrome function :)

– FAREH
Dec 22 '17 at 13:05 — Dec 22 '17 at 13:05

Kzrystof 2,00431321 · Accepted Answer · 2018-07-17 20:45:19Z

This is a short and efficient way of checking palindrome.

bool checkPalindrome(string inputString) {



    int length = inputString.Length;

    for(int i = 0; i < length/2; i++){

        if(inputString[i] != inputString[length-1-i]){

            return false;

        }

    }



    return true;



}

Tanvir AnowarTanvir Anowar 456 · Accepted Answer · 2018-08-07 19:39:14Z

public bool Solution(string content)

    {

        int length = content.Length;



        int half = length/2;



        int isOddLength = length%2;



        // Counter for checking the string from the middle 

        int j = (isOddLength==0) ? half:half+1;



        for(int i=half-1;i>=0;i--)

        {                

            if(content[i] != content[j])

            {

               return false;

            }

            j++;



        }

        return true;

    }

Bonus points if you add some details on how this works for future visitors. A couple of test cases, too, maybe? — Aug 7 '18 at 20:08

Jerko ViskovJerko Viskov 1 · Accepted Answer · 2019-01-30 17:47:22Z

    public  bool MojTestPalindrome (string word)

    {

        bool yes = false;



        chartest1 = word.ToArray();

        char test2 = test1.Reverse().ToArray();

        for (int i=0; i< test2.Length; i++)

        {



            if (test1[i] != test2[test2.Length - 1 - i])

            {



                yes = false;

                break;



            }

            else {   

                yes = true;





            }

        }

        if (yes == true)

        {

            return true;

        }

        else



            return false;                

    }

score -1 · Accepted Answer · 2018-01-11 08:04:24Z

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;





class palindrome

{

    static void Main(string args)

    {

        Console.Write("Enter a number:");

        string panstring = Console.ReadLine();

        Palindrome(panstring);

        Console.ReadKey();

    }

     static int index = 0;

     public static void Palindrome(string strexcluding)

    {

        try

        {

            string reversecounter = string.Empty;



            for (int i = strexcluding.Length - 1; i >= 0; i--)

            {

                if (strexcluding[i].ToString() != null)

                    reversecounter += strexcluding[i].ToString();

            }

            if (reversecounter == strexcluding)

            {

                Console.WriteLine("Palindrome Number: " + strexcluding);

            }

            else

            {

                Sum(strexcluding);

            }

        }

         catch(Exception ex)

        {

            Console.WriteLine(ex.ToString());

        }

    }



    public static void Sum(string stringnumber)

    {

        try

        {

            index++;

            string number1 = stringnumber;

            string number2 = stringnumber;

            string array = new string[number1.Length];

            string obtained = string.Empty;

            string sreverse = null;



            Console.WriteLine(index + ".step : " + number1 + "+" + number2);



            for (int i = 0; i < number1.Length; i++)

            {

                int temp1 = Convert.ToInt32(number1[number1.Length - i - 1].ToString());

                int temp2 = Convert.ToInt32(number2[number2.Length - i - 1].ToString());



                if (temp1 + temp2 >= 10)

                {

                    if (number1.Length - 1 == number1.Length - 1 - i)

                    {

                        array[i] = ((temp1 + temp2) - 10).ToString();

                        obtained = "one";

                    }

                    else if (number1.Length - 1 == i)

                    {

                        if (obtained == "one")

                        {

                            array[i] = (temp1 + temp2 + 1).ToString();

                        }

                        else

                        {

                            array[i] = (temp1 + temp2).ToString();

                        }

                    }

                    else

                    {

                        if (obtained == "one")

                        {

                            array[i] = ((temp1 + temp2 + 1) - 10).ToString();

                        }

                        else

                        {

                            array[i] = ((temp1 + temp2) - 10).ToString();

                            obtained = "one";

                        }



                    }

                }



                else

                {

                    if (obtained == "one")

                        array[i] = (temp1 + temp2 + 1).ToString();

                    else

                        array[i] = (temp1 + temp2).ToString();

                    obtained = "Zero";

                }



            }



            for (int i = array.Length - 1; i >= 0; i--)

            {

                if (array[i] != null)

                    sreverse += array[i].ToString();

            }



            Palindrome(sreverse);

        }

        catch(Exception ex)

        {

            Console.WriteLine(ex.ToString());

        }

    }

}

搜尋此網誌

Bdtjtk

Check if a string is a palindrome

29 Answers
29

Your Answer

Post as a guest

29 Answers
29

29 Answers
29

Post as a guest

Popular posts from this blog

Monofisismo

Angular Downloading a file using contenturl with Basic Authentication

Olmecas

Check if a string is a palindrome

29 Answers 29

Your Answer

Sign up or log in

Post as a guest

Post as a guest

29 Answers 29

29 Answers 29

Sign up or log in

Post as a guest

Post as a guest

Sign up or log in

Post as a guest

Sign up or log in

Post as a guest

Sign up or log in

Post as a guest

Popular posts from this blog

Monofisismo

Angular Downloading a file using contenturl with Basic Authentication

Olmecas

29 Answers
29

29 Answers
29

29 Answers
29