[C#] 함수 method

using System;

namespace MyFirstProgram
{
    internal class Program
    {
        static void Main(string[] args) // main method
        {

            String name = "JoLab";
            int age = 22;

            singHappyBirthday_1(); // 그냥 아무것도 없는 함수
            singHappyBirthday_2(name); // 매개변수가 있는 함수 1
            singHappyBirthday_3(name, age); // 매개변수가 있는 함수 2


        }

        static void singHappyBirthday_1()
        {
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine("Happy birthday dear YOU!");
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine();
        }
        static void singHappyBirthday_2(String name)
        {
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine("Happy birthday dear " + name);
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine();
        }

        static void singHappyBirthday_3(String name, int age)
        {
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine("Happy birthday dear " + name);
            Console.WriteLine("You are " + age + " years old!");
            Console.WriteLine("Happy birthday to you!");
            Console.WriteLine();
        }
    }
}