Day 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    public struct city
    {
        public string name;
        public int inhabitats;
    }
    class Program
    {
        static void Main(string[] args)
        {
            city[] array = new city[500];
            int citynumber = 0;
            while (1==1)
            {
                Console.WriteLine("1 .- Add a new city");
                Console.WriteLine("2 .- View all cities");
                Console.WriteLine("3 .- Modify a record");
                Console.WriteLine("4 .- Insert a new record");
                Console.WriteLine("5 .- Delete a record");
                Console.WriteLine("6 .- Search in the records");
                Console.WriteLine("7 .- Correct the capitalization of the names");

                byte choice = Convert.ToByte(Console.ReadLine());
                switch (choice)
                {
                    case 1:
                        Console.WriteLine("Write name");
                        array[citynumber].name = Console.ReadLine();
                        Console.WriteLine("Write population");
                        array[citynumber].inhabitats = Convert.ToInt32(Console.ReadLine());
                        citynumber++;
                        break;
                    case 2:
                        for (int i = 0; i < citynumber; i++)
                        {
                            Console.WriteLine("Name of city: {0}", array[i].name);
                            Console.WriteLine("Population: {0}", array[i].inhabitats);
                        }
                        break;
                    case 3:
                        Console.WriteLine("Choose city");
                        int chosenc = Convert.ToInt32(Console.ReadLine());
                        string decision;

                        Console.WriteLine("Change population? Y/N");
                        decision = Console.ReadLine();
                        if (decision == "Y")
                        {
                            Console.WriteLine("Write population");
                            array[chosenc].inhabitats = Convert.ToInt32(Console.ReadLine());
                        }


                        Console.WriteLine("Change name? Y/N");
                        decision = Console.ReadLine();
                        if (decision == "Y")
                        {
                            Console.WriteLine("Write name");
                            array[chosenc].name = Console.ReadLine();
                        }
                        break;
                    case 4:
                        Console.WriteLine("Choose city number");
                        int chosennumber = Convert.ToInt32(Console.ReadLine());
                        for (int i = chosennumber; i < citynumber; i++)
                        {
                            array[i + 1] = array[i];
                        }

                        Console.WriteLine("Write name");
                        array[chosennumber].name = Console.ReadLine();
                        Console.WriteLine("Write population");
                        array[chosennumber].inhabitats = Convert.ToInt32(Console.ReadLine());

                        break;
                    case 5:
                        Console.WriteLine("Choose city number");
                        int delnumb = Convert.ToInt32(Console.ReadLine());
                        for (int i = delnumb; i < citynumber; i++)
                        {
                            array[i] = array[i + 1];
                        }
                        break;
                    case 6:
                        Console.WriteLine("Which city do you want to find? Write the name");
                        string findname = Console.ReadLine();
                        for (int i = 0; i <= citynumber; i++)
                        {
                            if (array[i].name == findname)
                            {
                                Console.WriteLine("Number {0}, name {1}, population {2}", i, array[i].name, array[i].inhabitats);
                            }
                        }
                        break;
                    case 7:
                        for (int i = 0; i <= citynumber; i++)
                        {
                            char.ToUpper(array[i].name[0]);
                        }
                        break;
                    case 0:
                        break;
                }

            }
        }
    }
}