using System;

​

public class Validate {

​

  public static bool IsNumericDigit(char c) {

    return '0' <= c && c <= '9';

  }

​

  public static bool HasNumericDigits(string s) {

    foreach (char c in s)

      if (IsNumericDigit(c)) return true;

    return false;

  }

}

public class Program

{

    public static void Main()

    {

        const int Capacity = 5;

        string[] Last = new string[Capacity];

        string[] First = new string[Capacity];

        string[] Middle = new string[Capacity];

        string[] Phone = new string[Capacity];

        double[] GPA = new double[Capacity];

        int size = 0;

        string lastname, firstname, middlename, phonenumber, input;

        bool ValidName;

        bool ValidGPA;

        bool ValidPhone;

        double studentGPA;

        // Get the list of students

        do {

            do

            {

                Console.WriteLine("Last name = ");

                lastname = Console.ReadLine();

                ValidName = !Validate.HasNumericDigits(lastname);

            } while (!ValidName);

            if (lastname == "") continue;

​

            do

            {

                Console.WriteLine("First name = ");

                firstname = Console.ReadLine(); 

                ValidName = !Validate.HasNumericDigits(firstname);

            } while (!ValidName);

​

            do

            {

                Console.WriteLine("Middle name = ");

                middlename = Console.ReadLine();

                ValidName = !Validate.HasNumericDigits(middlename);

            } while (!ValidName);

            do

            {

                Console.WriteLine("Phone number = ");

                phonenumber = Console.ReadLine();

                ValidPhone = !Validate.IsValidPhoneNumber(phonenumber);

            do 

            {

                Console.WriteLine("GPA = ");

                input = Console.ReadLine();

                ValidGPA = Double.TryParse(input, out studentGPA);

            } while (!ValidGPA);

            Last[size] = lastname;

            First[size] = firstname;

            Middle[size] = middlename;

            GPA[size] = studentGPA;

            size++;

        } while (lastname != "" && size < Capacity);

        // Print the student table

​

        // Console.WriteLine("Size {0}", size); 

​

        // const int field1 = 20;

        // const int field2 = 4;

        int[] field = new int[] { 20, 15, 15, 4 };

        string Header = "Last Name".PadRight(field[0]) + 

             "First Name".PadRight(field[1]) + "Middle Name".PadRight(field[2]) + 

             "GPA".PadRight(field[3]);

        string Separator = " ".PadLeft(field[0], '=') + 

            " ".PadLeft(field[1], '=') + 

            "".PadLeft(field[2], '=') + " ".PadLeft(field[3], '=');

        Console.WriteLine(Header);

        Console.WriteLine(Separator);

        double aveGPA = 0;

        double sumGPA = 0;

        for (int i = 0; i < size; i++)

        {

            Console.WriteLine(Last[i].PadRight(field[0]) + 

                              First[i].PadRight(field[1]) + Middle[i].PadRight(field[2]) + 

                              GPA[i].ToString().PadLeft(field[3]));

            sumGPA += GPA[i];

        }

        Console.WriteLine(Separator);

​

        aveGPA = sumGPA / size;

        Console.WriteLine("{0} student(s) with average age of {1}", size, aveGPA);

    }

}