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

public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};

        string[] names = presidents.OfType<string>().ToArray();
        foreach (string name in names)
            Console.WriteLine(name);
    }
}

    

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
public static void Main() {

string[] presidents = {“ant”, “Hard”, “Harrison”, “Hayes”, “Hoover”, “Jack”};

IEnumerable items = presidents
.TakeWhile((s, i) => s.Length < 10 && i < 5); foreach (string item in items) Console.WriteLine(item); } } [/csharp]

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

public class CaseInsensitiveComparer : IComparer<string> {
    public int Compare(string x, string y) {
        return string.Compare(x, y, true);
    }
}

public class MainClass {
    public static void Main() {

        string[] words = { "a", "A", "b", "B", "C", "c" };

        var sortedWords =
            words.OrderBy(a => a.Length)
                    .ThenByDescending(a => a, new CaseInsensitiveComparer());

        foreach (var s in sortedWords) {
            Console.WriteLine(s);
        }
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {

        string[] presidents = {"ant", "arding", "arrison", "eyes", "over", "Jackson"};

        IEnumerable<string> items = presidents.OrderBy(s => s.Length).ThenBy(s => s);

        foreach (string item in items)
            Console.WriteLine(item);
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {

        string[] presidents = {"ant", "arding", "arrison", "eyes", "over", "Jackson"};

        IEnumerable<string> items =
          presidents.OrderBy(s => s.Length).ThenByDescending(s => s);

        foreach (string item in items)
            Console.WriteLine(item);
    }
}

    

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
public static void Main() {
string[] presidents = {“1234567890123”, “Art”, “Buch”, “Bush”, “Car”, “land”};
IEnumerable items = presidents.TakeWhile(s => s.Length < 10); foreach (string item in items) Console.WriteLine(item); } } [/csharp]

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

public class MainClass {
    public static void Main() {

        int[] numbers = { 5, 4, 1, 3, 9};

        var first3Numbers = numbers.Take(3);

        Console.WriteLine("First 3 numbers:");
        foreach (var n in first3Numbers) {
            Console.WriteLine(n);
        }
    }
}