C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication1
{
    internal class Course
    {
        public int ID { get; set; }
        public string Subject { get; set; }
        public int Rank { get; set; }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            List<Course> courses = new List<Course>();
            courses.Add(new Course
            {
                ID = 1,
                Subject = "LINQ Tutorials",
                Rank = 5
            });

            courses.Add(new Course
            {
                ID = 2,
                Subject = ".NET Threading Tutorials",
                Rank = 4
            });

            courses.Add(new Course
            {
                ID = 3,
                Subject = "Learn WPF",
                Rank = 3
            });

            var result = courses.Where(c => c.Rank > 3);

            foreach (var course in result)
            {
                Console.WriteLine(course.Subject);
            }
        }
    }
}

 
using System;
using System.Collections.Generic;
using System.Linq;
​
namespace ConsoleApplication1
{
    internal class Course
    {
        public int ID { get; set; }
        public string Subject { get; set; }
        public int Rank { get; set; }
    }
​
    public class Program
    {
        public static void Main(string[] args)
        {
            List<Course> courses = new List<Course>();
            courses.Add(new Course
            {
                ID = 1,
                Subject = "LINQ Tutorials",
                Rank = 5
            });

Compilation error (line 98, col 15): Expected class, delegate, enum, interface, or struct
Compilation error (line 102, col 49): Expected class, delegate, enum, interface, or struct
Compilation error (line 102, col 60): Expected class, delegate, enum, interface, or struct
Compilation error (line 103, col 3): Type or namespace definition, or end-of-file expected