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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            first();
            second();
            third();
        }
        public static void first()
        {
            char g;
            int num = 1;
            int sum = 0;
            Console.WriteLine("click A to Add all numbers and hit 0 to stop");
            Console.WriteLine("click F to request a fibonacci numbers");
            Console.WriteLine("click R to request a random number between a given interval");
            switch (g = char.Parse(Console.ReadLine()))
            {
                case 'A':
                    while (num != 0)
                    {
                        Console.WriteLine("please enter a number");
                        num = int.Parse(Console.ReadLine());
                        if (num == 0)
                            Console.WriteLine(sum);
                        else
                            sum += num;

                    }
                    break;
                case 'F':
                    int a = 0, b = 1, c;
                    Console.WriteLine("please enter the numbers of fibonacci");
                    int s = num = int.Parse(Console.ReadLine());
                    //display the first two elements of fibonacci
                    Console.WriteLine(a);
                    Console.WriteLine(b);
                    for (int i = 0; i < s; i++)
                    {
                        c = a + b;
                        Console.WriteLine(c);
                        a = b;
                        b = c;

                    }
                    break;
                case 'R':
                    Console.WriteLine("please enter the first interval");
                    int x = int.Parse(Console.ReadLine());
                    Console.WriteLine("please enter the second interval");
                    int y = int.Parse(Console.ReadLine());
                    Random rnd = new Random();
                    int z = rnd.Next(x, y);
                    Console.WriteLine("the random number is " + z);

                    break;

            }
            Console.ReadLine();

        }
        public static void second()
        {

            int num = 1, sum = 0, i = 0, max = 0, ave = 0;

            Console.WriteLine("please enter number and hit 0 to stop,");
            while (num != 0)
            {

                Console.WriteLine("enter a number");
                num = int.Parse(Console.ReadLine());

                i++;
                if (num > max) max = num;
                sum += num;
                ave = sum / i+1;


            }
            char g;
            Console.WriteLine("click A to get average");
            Console.WriteLine("click B to get the max value");
            switch (g = char.Parse(Console.ReadLine()))
            {
                case 'A':
                    Console.WriteLine(ave);

                    break;
                case 'B':
                    Console.WriteLine(max);
                    break;
            }
            Console.ReadLine();
        }
        public static void third()
        {
            Console.WriteLine("please enter your height");
            double a = double.Parse(Console.ReadLine());
            Console.WriteLine("please enter your weight");
            double b = double.Parse(Console.ReadLine());
           double BMI = b / (a * a);
           Console.WriteLine("your BMI is "+BMI);
           if (BMI <18.5 || BMI> 25)
           {
               Console.WriteLine("its bad");
           }
           else
           {
               Console.WriteLine("its good");
           }
           Console.ReadLine();
        }
    }
}