using System;

public class Program

{

    public static void Main()

    {

        //1. Read input from user

        Console.WriteLine("Please enter a whole number.");

        string strInput = Console.ReadLine();

        //

        //2. Validate this input (check whether it is a valid whole number)

        //USE THIS ON HOMEWORK 3 for validation

        int iScore;

        //if double format, use Double.TryParse

        bool IsValidNumber = Int32.TryParse(strInput, out iScore);

        Console.WriteLine(IsValidNumber);

        Console.WriteLine(iScore);

        if(IsValidNumber == false);

        {

                Console.WriteLine("Please enter a valid number");

                return;

                //return; stops the code so that it doesn't keep running and instead goes back to the beginning of the code, this is important?

        }

        //it will give true if the number is valid, int32 checks to see if user input is an integer. (type 65 get true, type 65.2, get false)

        //3. Show the following information 

        // Input: >= 90, show message "You get A".

        // Input: 80 ~ 90, show message "You get B".

        // Input: 70 ~ 80, show message "You get C".

        // Input: 60 ~ 70, show message "You get D".

        // Input: <= 60, show message "You get F".

        if (iScore >= 90)

        {

            Console.WriteLine("You get an A");

        }

        else if (iScore >=80)

        {

            Console.WriteLine("You get a B");

        }

        else if (iScore >=70)

        {

            Console.WriteLine("You get a C");

        }

        else if (iScore >=60)

        {

            Console.WriteLine("You get a D");

        }

        else;

        {

            Console.WriteLine("You get a F");

        }

        //4. For individual's score greater than 90, check his/her major

        //Show "Congratulations! You are one of the best students in IS" if the major is IS

​

}