Question

I have created a scrabble game with a computer opponent. If a blank tile is found in the computer’s rack during the word generation if needs to be swapped out for every letter in the alphabet. I have my current solution to solve this problem below, but was wondering if there is a better more efficient way to accomplish this task.

if (str.Contains("*"))
                {
                    char c = 'A';
                    String made = "";
                    while(c < 'Z')
                    {
                        made = str.ReplaceFirst("*", c.ToString());
                        if (!made.Contains("*"))
                        {
                            wordsMade.Add(made);
                            if (theGame.theTrie.Search(made) == Trie.SearchResults.Found)
                            {
                                validWords.Add(made);
                            }
                        }
                        else
                        {
                            char ch = 'A';
                            String made2 = "";
                            while (ch < 'Z')
                            {
                                made2 = made.ReplaceFirst("*", c.ToString());
                                wordsMade.Add(made2);
                                if (theGame.theTrie.Search(made2) == Trie.SearchResults.Found)
                                {
                                    validWords.Add(made2);
                                }
                                ch++;
                            }
                        }
                        c++;
                    }

Answer 1

There’s a lot of duplicated code here that can be refactored.

This routine is duplicated, and can be put into a separate method:

wordsMade.Add(made2);
if (theGame.theTrie.Search(made2) == Trie.SearchResults.Found)
{
   validWords.Add(made2);
}

To something like this

void addWord(string newWordMade){
    wordsMade.Add(newWordMade);
    if (theGame.theTrie.Search(newWordMade) == Trie.SearchResults.Found)
    {
       validWords.Add(newWordMade);
    }
}

This loop construct is also duplicated:

char ch = 'A';
String made2 = "";
while (ch < 'Z')
{
   made2 = made.ReplaceFirst("*", c.ToString());
   wordsMade.Add(made2);
   if (theGame.theTrie.Search(made2) == Trie.SearchResults.Found)
   {
      validWords.Add(made2);
   }
   ch++;
}

Combining the previous refactor with this one, with a slick lambda, would yield something like this:

void loopCharactersAndDoThis(Action<char> DoThis) {
    char ch = 'A';
    while (ch < 'Z')
    {
       DoThis(ch);
       ch++;
    }
}

else
{
   loopCharactersAndDoThis(ch => {
      string made2 = made.ReplaceFirst("*", c.ToString());
      addWord(made2);
   });
}

Or even just:

else
{
   loopCharactersAndDoThis(ch => addWord(made.ReplaceFirst("*", c.ToString())));
}