lab2_functions

using System;
using System.Collections.Generic;
using static System.String;

namespace _2020_12_24_lab2
{
    class Program
    {
        static void Copies(string s, ref string s1, int n)
        {
            for (int i = 0; i < n; i++)
                Concat(ref s1, s);
        }
        static int Words(string s)
        {
            int i = 0;
            bool isLetter = false;
            foreach (char ch in s)
            {
                bool currentIsLetter = Char.IsLetter(ch);
                if (currentIsLetter && !isLetter)
                    i++;
                isLetter = currentIsLetter;
            }
            return i;
        }
        static void Concat(ref string s1, string s2)
        {
            s1 += s2;
        }
        static string[] Parse(string s, char t)
        {
            string[] result = { "", "" };
            bool find = false;
            foreach (char ch in s)
            {
                if (ch == t)
                    find = true;
                result[find ? 1 : 0] += ch;
            }
            return result;
        }
        static void Center(string s1, ref string s2, int l)
        {
            // if l is odd then the middle character replaced with s1
            // if l more than length of s2 then add a space to fit the lenght
            if (l < 2)
                s2 = s1;
            else
            {
                int secondHalfStart = l / 2 + l % 2;
                if (secondHalfStart < s2.Length)
                {
                    string trail = s2.Substring(secondHalfStart) + new String(' ', l / 2 - (s2.Length - secondHalfStart)); // fill second half with space characters
                    s2 = s2.Substring(0, l / 2) + s1 + trail;
                }
                else
                {
                    s2 += new String(' ', l / 2 - s2.Length) + s1 + new String(' ', l / 2); // fill first half and add s1 and add fake secondhalf
                }
            }
        }
        static void Delete(ref string s, int n, int l)
        {
            string trail = (s.Length > n + l) ? s.Substring(n + l) : "";
            s = ((n < s.Length) ? s.Substring(0, n) : s) + trail;
        }
        static void Left(ref string s, int l)
        {
            if (l <= s.Length)
                return;
            s += new String(' ', l - s.Length);
        }
        static void Right(ref string s, int l)
        {
            if (l <= s.Length)
                return;
            s = s.Insert(0, new String(' ', l - s.Length));
        }
        static string[] SubWord(string s, int n, int l)
        {
            List<string> result = new List<string>();

            if (l > 0)
            {
                string temp = "";
                bool isLetter = false;
                int currentWordIndex = 0;
                foreach (char ch in s)
                {
                    bool currentIsLetter = Char.IsLetter(ch);
                    if (currentIsLetter && !isLetter)
                    {
                        currentWordIndex++;
                        if (currentWordIndex > n + l)
                            break;
                    }
                    if (currentWordIndex > n)
                    {
                        if (!currentIsLetter && isLetter)
                        {
                            result.Add(temp);
                            temp = "";
                        }
                        if (currentIsLetter)
                            temp += ch;
                    }
                    isLetter = currentIsLetter;
                }

                if (temp.Length > 0)
                    result.Add(temp);
            }

            return result.ToArray();
        }
        static void Replace(ref string s, string s1, string s2)
        {
            string source = s;
            Func<int, bool> checkForEquality = (int startPosition) => (!(source.Length - s1.Length - startPosition < 0) && (source.Substring(startPosition, s1.Length) == s1));
            s = "";
            for (int i = 0; i < source.Length;)
            {
                if (checkForEquality(i))
                {
                    s += s2;
                    i += s1.Length;
                }
                else
                {
                    s += source[i];
                    i++;
                }
            }
        }
        static void Main(string[] args)
        {
            string s1 = "something";
            Copies("-blah", ref s1, 3);
            Console.WriteLine(Format("Copies(\"-blah\", ref s1, 3): {0}", s1));

            Console.WriteLine(Format("Words(\"{0}\"): {1}", s1, Words(s1)));

            Concat(ref s1, " uhoh");
            Console.WriteLine(Format("Concat(ref s1, \" uhoh\"): {0}", s1));

            {
                var strings = Parse(s1, '-');
                Console.WriteLine(Format("Parse(s1, '-'):\n\t{0}\n\t{1}", strings[0], strings[1]));
            }

            Console.Write(Format("Center(\"ooga\", \"{0}\", {1}): ", s1, s1.Length));
            Center("ooga", ref s1, s1.Length);
            Console.WriteLine(s1);

            Console.Write(Format("Delete(\"{0}\", {1}, 2): ", s1, s1.Length - 3));
            Delete(ref s1, s1.Length - 3, 2);
            Console.WriteLine(s1);

            { // do not modify the s1
                string temp = s1;
                Left(ref temp, s1.Length + 2);
                Console.WriteLine(Format("Left(\"{0}\", {1}): {2}", s1, s1.Length + 2, temp));

                temp = s1;
                Right(ref temp, s1.Length + 2);
                Console.WriteLine(Format("Right(\"{0}\", {1}): {2}", s1, s1.Length + 2, temp));
            }

            {
                Console.WriteLine(Format("SubWord(\"{0}\", {1}, {2}):", s1, 1, 2));
                var strings = SubWord(s1, 1, 2);
                foreach (string str in strings)
                    Console.WriteLine(Format("\t{0}", str));
            }

            Console.Write(Format("Replace(\"{0}\", \"{1}\", \"{2}\"): ", s1, "blah", "ouch"));
            Replace(ref s1, "blah", "ouch");
            Console.WriteLine(s1);
        }
    }
}