1. do
2. while
3. for
4. foreach, in

• do (C# Reference)
• while (C# Reference)
• for (C# reference)
• foreach, in (C# reference)

1.do

using System;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = 0;
            do
            {
                Console.WriteLine(n);
                n++;
            } while (n < 5);
        }
    }
}

// The example displays the following output:
//      0
//      1
//      2
//      3
//      4

2.while

using System;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = 0;
            while (n < 5)
            {
                Console.WriteLine(n);
                n++;
            }
        }
    }
}

// The example displays the following output:
//      0
//      1
//      2
//      3
//      4

3.for

using System;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            for (int i = 0; i < 5; i++)
            {
                Console.WriteLine(i);
            }
        }
    }
}

// The example displays the following output:
//      0
//      1
//      2
//      3
//      4

4.foreach, in

using System;
using System.Collections.Generic;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var fibNumbers = new List<int> { 0, 1, 1, 2, 3, 5, 8, 13 };
            int count = 0;
            foreach (int element in fibNumbers)
            {
                count++;
                Console.WriteLine("Element #{0}: {1}", count, element);
            }
            Console.WriteLine("Number of elements: {0}", count);
        }
    }
}

// The example displays the following output:
//      Element #1: 0
//      Element #2: 1
//      Element #3: 1
//      Element #4: 2
//      Element #5: 3
//      Element #6: 5
//      Element #7: 8
//      Element #8: 13
//      Number of elements: 8