using System;

using System.Collections.Generic;

​

IEnumerable<int> numbers = GetNumbers();

foreach (int n in numbers)

{

    Console.WriteLine($"取得 {n}");

}

​

static IEnumerable<int> GetNumbers()

{

    var numbers = new int[] { 1, 2, 3 };

    foreach (int n in numbers)

    { 

        yield return n;

        Console.WriteLine($"回傳 {n} 之後");

    }

}

​