1 задача

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

namespace _01.Students
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("How many students?");
            int n = int.Parse(Console.ReadLine());
            double[] grades = new double[n];
            int[] failed = new int[n];
            int sreden = 0, good = 0, verygood = 0, excelent = 0;

            double averageGrade = 0;
            int j = 0;
            for (int i = 0; i < n; i++)
            {
                grades[i] = double.Parse(Console.ReadLine());
                while (grades[i] < 2 || grades[i] > 6)
                {
                    Console.WriteLine("Greshna ocenka. Napishi nova: ");
                    grades[i] = double.Parse(Console.ReadLine());
                }
                if (grades[i] == 2)
                {
                    failed[j] = i + 1;
                    j++;
                }
                switch (grades[i])
                {
                    case 3:
                        sreden++;
                        break;
                    case 4:
                        good++;
                        break;
                    case 5:
                        verygood++;
                        break;
                    case 6:
                        excelent++;
                        break;
                 }
                averageGrade += grades[i];
            }

            averageGrade /= n;

            Console.Write("Nomera na uchenici sus slab 2: ");
            for (int i = 0; i < n; i++)
            {
                if (failed[i] == 0)
                {
                    break;
                }
                Console.Write(failed[i] + " ");
            }
            Console.WriteLine();
            Console.WriteLine($"Average grade is: {averageGrade:F2}");
            Console.WriteLine($"Broi na uchenici s 2: {failed.Count(g => g != 0)}");
            Console.WriteLine($"Broi na uchenici s 3: {sreden}");
            Console.WriteLine($"Broi na uchenici s 4: {good}");
            Console.WriteLine($"Broi na uchenici s 5: {verygood}");
            Console.WriteLine($"Broi na uchenici s 6: {excelent}");




        }
    }
}