Lab18-3-2

using System.Text.RegularExpressions;

namespace ConsoleApp1
{
    class Program
    {
        const int maxLineLength = 200;
        const string sentenceEnds = ".!?";
        const int minSentences = 3;
        const string punctuationSigns = ",:;-";

        static bool checkPunctuation(string line)
        {
            Regex punctuation = new Regex(@"^([A-ZА-Я]{1}\w*(,|:|;|-){0,1}(\s((\w+-\w+)+|\w+)(,|:|;|-){0,1})*((\w+-\w+)+|(\w+)){1}(\.\.\.|!|\?|\.){1}){3,}$");
            return punctuation.IsMatch(line);
        }

        /*static int calcLineSentences(string line)
        {
            string temp = string.Empty;
            int counter = 0;
            foreach (char symbol in line)
            {
                if (sentenceEnds.Contains(symbol) && temp.Length > 0)
                {
                    temp = string.Empty;
                    counter++;
                }
                else
                    temp += symbol;
            }
            return counter;
        }

        static string[] getLineSentences(string line)
        {
            string[] sentences = new string[calcLineSentences(line)];
            string temp = string.Empty;
            int i = 0;
            foreach(char symbol in line)
            {
                if(sentenceEnds.Contains(symbol) && temp.Length > 0)
                {
                    sentences[i++] = temp;
                    temp = string.Empty;
                }
                else
                    temp += symbol;
            }
            return sentences;
        }

        static bool checkSentences(string[] sentences)
        {
            bool isCorrect = sentences.Length >= minSentences;
            int i = 0;
            while(isCorrect && i < sentences.Length)
            {
                if (checkPunctuation(sentences[i]))
                    i++;
                else
                    isCorrect= false;
            }
            return isCorrect;
        }

        static bool checkLine(string line)
        {
            bool isCorrect = line.Length >= maxLineLength;
            return isCorrect & checkSentences(getLineSentences(line));
        }*/

        static string excludeEachNSymbol(string line, int N)
        {
            string cutLine = string.Empty;
            for (int i = 0; i < line.Length; i++)
                if ((i + 1) % N != 0)
                    cutLine += line[i];
            return cutLine;
        }

        static void Main(string[] args)
        {
            Console.Write("Enter a line: ");
            string line = Console.ReadLine();
            if (line.Length <= maxLineLength && checkPunctuation(line))
            {
                if ((line.Length & 1) == 0)
                    Console.Write(excludeEachNSymbol(line, 2));
                else
                    Console.Write("The string is of odd length.");
            }
            else
                Console.Write("The string is not correct!");
        }
    }
}