static void _Main(string[] args)
        {
            if (args[0] != String.Empty)
            {
                IEnumerable <string> linesOfFile = ReadFile(args[0]);

                foreach (var singleLine in linesOfFile)
                {
                    PercentageRatios percentageRatios = GetPercentageRatios(singleLine.ToCharArray());

                    Console.WriteLine("lowercase: {0} uppercase: {1}",
                                      FormatNumberForDisplay(percentageRatios.LowercasePercentage),
                                      FormatNumberForDisplay(percentageRatios.UppercasePercentage));
                }
            }
        }
        private static PercentageRatios GetPercentageRatios(char[] letters)
        {
            PercentageRatios calculatedPercentageRatios = new PercentageRatios();

            double lowerCaseAmount = 0;
            double upperCaseAmount = 0;

            foreach (var letter in letters)
            {
                if (char.IsUpper(letter))
                {
                    upperCaseAmount++;
                }
                else
                {
                    lowerCaseAmount++;
                }
            }

            calculatedPercentageRatios.LowercasePercentage = Math.Round((lowerCaseAmount / letters.Length) * 100, 2);
            calculatedPercentageRatios.UppercasePercentage = Math.Round((upperCaseAmount / letters.Length) * 100, 2);

            return(calculatedPercentageRatios);
        }