using System;

namespace Any_function
{
    internal class Program
    {
        static void Main(string[] args)
        {
            String fullName = "CSharp";
            String phoneNumber = "123-456-7890";

            //fullName = fullName.toUpper(); - isupper()
            //fullName = fullName.toLower(); - islower()
            //Console.WriteLine(fullName);

            phoneNumber = phoneNumber.Replace("-", "/");
            Console.WriteLine(phoneNumber);

            String userName = fullName.Insert(0,"#");
            Console.WriteLine(userName);

            Console.WriteLine(fullName.Length);

            String firstName = fullName.Substring(0,1); //part of String from 0 to 1
            String lastName = fullName.Substring(1, 5); 
            Console.WriteLine(firstName+' '+lastName); //Concat firstName and lastName
        }
    }
}