using System.Collections.Generic;
public static void Main()
var a = new List<int> { 1, 2, 3 };
Console.WriteLine(string.Join(", ", a.Select(i => i.ToString())));
Console.WriteLine(string.Join(", ", a.Select(i => i.ToString())));
Console.WriteLine(string.Join(", ", a.Select(i => i.ToString())));
public static void Foo(IEnumerable<int> a)
public static void Bar(List<int> a)