---

public void Calculate()
    {
        foreach(string sentence in sentenceList)
        {
            sentences++;

            for (int i = 0; i < sentence.Length; i++)
            {
                if (vowelsArray.Contains(sentence[i]))
                {
                    vowels++;
                }
                else if (consonantsArray.Contains(sentence[i]))
                {
                    consonants++;
                }
                else if (char.IsUpper(sentence[i]))
                {
                    upperCaseLetters++;
                }
                else if (char.IsLower(sentence[i]))
                {
                    lowerCaseLetters++;
                }
            }
        }
    }