/// <summary>
        /// Counts the amount of certain character occasions in a string.
        /// <para>Has a "skip list" which prevents checking a character more than once.
        /// If a character is found more than once => skip current character.</para>
        /// </summary>
        /// <param name="stringToSearchIn"></param>
        /// <returns></returns>
        public static char CountEachCharacterSearch(string stringToSearchIn)
        {
            char        foundCharacter    = default;
            List <char> checkedCharacters = new List <char>();
            int         stringLength      = stringToSearchIn.Length;

            for (int i = 0; i < stringLength; i++)
            {
                char currentCharacter = stringToSearchIn[i];
                // Don't check the same character twice
                if (checkedCharacters.Contains(currentCharacter))
                {
                    continue;
                }

                // If the character count is higher than 1 - add it to "skip list" so that you don't check it again
                if (StringCheck.CharacterRepeats(stringToSearchIn, currentCharacter))
                {
                    checkedCharacters.Add(currentCharacter);
                    continue;
                }
                else
                // If the count is equal to 1 (can't be lower, because we are checking it from the existing string) => character found
                {
                    foundCharacter = currentCharacter;
                    break;
                }
            }

            return(foundCharacter);
        }