How do I swap two characters in a string variable?

Question

I have a string variable. I want to swap the two characters in the string word. I want to randomly swap two characters which are close to each other.

This is what I have done: I have done like this but in some words I get error.

string word = txtWord.Text;
Random rand = new Random();
int randomNumber= rand.Next(0, word.Length);
string swappedWord = SwapCharacters(lastWord, randomNumber, randomNumber + 1);

private string SwapCharacters(string value, int position1, int position2)
{
    char[] array = value.ToCharArray(); // Convert a string to a char array
    char temp = array[position1]; // Get temporary copy of character
    array[position1] = array[position2]; // Assign element
    array[position2] = temp; // Assign element
    return new string(array); // Return string
}

Try rand.Next(0, word.Length - 1);

L.B
– L.B

2014-03-06 06:57:05 +00:00
Commented Mar 6, 2014 at 6:57 — L.B
– L.B, Commented Mar 6, 2014 at 6:57
What is the error you are getting?

AbhinavRanjan
– AbhinavRanjan

2014-03-06 06:57:45 +00:00
Commented Mar 6, 2014 at 6:57 — AbhinavRanjan
– AbhinavRanjan, Commented Mar 6, 2014 at 6:57
@L.B wasn't the higher bound non-inclusive?

Mario Stoilov
– Mario Stoilov

2014-03-06 06:58:17 +00:00
Commented Mar 6, 2014 at 6:58 — Mario Stoilov
– Mario Stoilov, Commented Mar 6, 2014 at 6:58
@MarioStoilov see the next line randomNumber + 1

L.B
– L.B

2014-03-06 06:59:14 +00:00
Commented Mar 6, 2014 at 6:59 — L.B
– L.B, Commented Mar 6, 2014 at 6:59
@L.B ah, yes. Didn't see that one.

Mario Stoilov
– Mario Stoilov

2014-03-06 07:00:13 +00:00
Commented Mar 6, 2014 at 7:00 — Mario Stoilov
– Mario Stoilov, Commented Mar 6, 2014 at 7:00

Bhupendra Shukla · Accepted Answer · 2014-03-06 07:09:08Z

3

Use a StringBuilder:

//If you want to replace

StringBuilder sb = new StringBuilder(theString);
    sb[index] = newChar;
    theString = sb.ToString();

//Swap

 string input = "AXBYCZ"; //Sample String
    StringBuilder output = new StringBuilder();

    char[] characters = input.ToCharArray();

    for (int i = 0; i < characters.Length; i++)
    {
      if (i % 2 == 0)
      {
        if((i+1) < characters.Length )
        {
          output.Append(characters[i + 1]);
        }
                   output.Append(characters[i]);
      }
    }

answered Mar 6, 2014 at 7:09

Bhupendra Shukla

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Comments

pareto · Accepted Answer · 2014-03-06 06:58:33Z

1

Just change the line as below:

int randomNumber= rand.Next(0, word.Length -1 );

Let's see if it works.

answered Mar 6, 2014 at 6:58

pareto

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3 Comments

EM10 Over a year ago

When I do this. I get it right but if the word is only 1 character I will get errors when I change the position of the word in the swapCharaters() method.

pareto Over a year ago

This is so because there is only one character in the string and in your method you are passing 'randomNumber+1' as well. Just put a check before it that says

pareto Over a year ago

if (randomNumber < word.Length -1) string swappedWord = SwapCharacters(lastWord, randomNumber, randomNumber + 1); else string swappedWord = SwapCharacters(lastWord, randomNumber, randomNumber); I hope this will help.

bit · Accepted Answer · 2014-03-06 06:58:15Z

0

Try this. Also add checks if the word is empty.

int randomNumber= rand.Next(0, word.Length - 1);

answered Mar 6, 2014 at 6:58

bit

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Comments

user3386894 · Accepted Answer · 2014-03-06 08:07:30Z

0

Try this code. It is easiest to change your code

int randomNumber= rand.Next(0, word.Length-2);

answered Mar 6, 2014 at 8:07

user3386894

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