task18

using System;
using System.Text;

public class Program
{
    public static void Main()
    {
        string[] names = new string[0];
        string[] positions = new string[0];

        string choose;
        bool isRun = true;
        while (isRun)
        {
            Console.WriteLine("\nInput number of action : ");
            Console.WriteLine("1. Add case.\n" +
                              "2. Output all cases.\n" +
                              "3. Remove case.\n" +
                              "4. Search case on name.\n" +
                              "5. Exit.");

            choose = Console.ReadLine();
            switch (choose)
            {
                case "1":
                    AddCase(ref names, ref positions);
                    break;
                case "2":
                    OutputCases(names, positions);
                    break;
                case "3":
                    RemoveCase(ref names, ref positions);
                    break;
                case "4":
                    SearchCase(names, positions);
                    break;
                case "5":
                    isRun = false;
                    break;
                default:
                    Console.WriteLine("You write wrong number of command.");
                    break;
            }
        }
    }

    public static void AddCase(ref string[] names, ref string[] positions)
    {
        string name;
        string position;
        Console.WriteLine("Input name of person : ");
        name = Console.ReadLine();
        AddElement(ref names, name);
        Console.WriteLine("Input position of person : ");
        position = Console.ReadLine();
        AddElement(ref positions, position);
    }

    public static void AddElement(ref string[] array, string element)
    {
        string[] arrayNew = new string[array.Length + 1];

        for (int i = 0; i < array.Length; ++i)
            arrayNew[i] = array[i];
        arrayNew[array.Length] = element;

        array = arrayNew;
    }

    public static void SearchCase(string[] names, string[] positions)
    {
        bool isFind = true;
        bool isFound = false;
        string input;

        Console.WriteLine("Please input name of person : ");
        input = Console.ReadLine();
        for (int i = 0; isFind && i < names.Length; ++i)
        {
            if (names[i].Equals(input))
            {
                isFound = true;
                isFind = false;
                Console.WriteLine($"{i}. {names[i]} - {positions[i]}");
            }
        }

        if (isFound == false)
        {
            Console.WriteLine("Cannot find person");
        }
    }

    public static void OutputCases(string[] names, string[] positions)
    {
        for (int i = 0; i < names.GetLength(0); ++i)
            Console.Write($"{i}. {names[i]} - {positions[i]} ");
        Console.WriteLine();
    }

    public static void RemoveCase(ref string[] names, ref string[] positions)
    {
        if (names.Length != 0)
        {
            int caseIndex = 0;
            bool isInput = true;
            while (isInput)
            {
                Console.WriteLine($"Amount of cases : {names.Length}");
                Console.WriteLine("Please type a number of case : ");
                caseIndex = Convert.ToInt32(Console.ReadLine());
                if (caseIndex >= 0 && caseIndex < names.Length)
                    isInput = false;
            }
            RemoveElement(ref names, caseIndex);
            RemoveElement(ref positions, caseIndex);
        }
    }

    public static void RemoveElement(ref string[] array, int index)
    {
        string[] arrayNew = new string[array.Length - 1];

        for (int i = 0; i < index; ++i)
            arrayNew[i] = array[i];

        for (int i = index, j = index + 1; j < array.Length; ++i, ++j)
            arrayNew[i] = array[j];

        array = arrayNew;
    }
}