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 jones = presidents.Where(n => n.Equals("H")).DefaultIfEmpty().First();
        if (jones != null)
            Console.WriteLine("H was found.");
        else
            Console.WriteLine("H was not found.");
    }
}

    

   
 

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 jones = presidents.Where(n => n.Equals("H")).First();
        if (jones != null)
            Console.WriteLine("H was found");
        else
            Console.WriteLine("H was not found");

    }
}

    

   
 

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 name =
          presidents.Where(n => n.Equals("H")).DefaultIfEmpty("Missing").First(); Console.WriteLine(name);

    }
}

    

   
 
using System.Drawing;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

public class Book {
    public String Title { get; set; }

    public override String ToString() {
        return Title;
    }
}
public class FormBooks : Form {

    static public Book[] Books =
    {
      new Book {Title="F"},
      new Book {Title="B"}
    };
    public FormBooks() {
        InitializeComponent();
    }

    private void FormStrings_Load(object sender, EventArgs e) {
        String[] books = { "F", "A", "B", "R", "B" };

        var query =
          from book in books
          where book.Length > 10
          orderby book
          select new { Book = book.ToUpper() };

        dataGridView1.DataSource = query.ToList();
    }
    private void InitializeComponent() {
        this.dataGridView1 = new System.Windows.Forms.DataGridView();
        ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).BeginInit();
        this.SuspendLayout();
        //
        // dataGridView1
        //
        this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
        this.dataGridView1.Dock = System.Windows.Forms.DockStyle.Fill;
        this.dataGridView1.Location = new System.Drawing.Point(10, 10);
        this.dataGridView1.Name = "dataGridView1";
        this.dataGridView1.Size = new System.Drawing.Size(272, 251);
        this.dataGridView1.TabIndex = 0;
        //
        // FormStrings
        //
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(292, 271);
        this.Controls.Add(this.dataGridView1);
        this.Name = "FormStrings";
        this.Padding = new System.Windows.Forms.Padding(10);
        this.Text = "FormStrings";
        this.Load += new System.EventHandler(this.FormStrings_Load);
        ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).EndInit();
        this.ResumeLayout(false);

    }
    private System.Windows.Forms.DataGridView dataGridView1;
    public static void Main() {
        Application.Run(new FormBooks());
    }
}

    

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

public class MainClass {
public static void Main() {

List customers = GetCustomerList();

var orderCounts =
from c in customers
select new { c.CustomerId, OrderCount = c.Orders.Count() };

Console.Write(orderCounts);
}
static List GetCustomerList() {
List empTree = new List();
empTree.Add(new Product { ProductName = “A”, Category = “O”, UnitPrice = 12, UnitsInStock = 5, Total = 36, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
empTree.Add(new Product { ProductName = “B”, Category = “O”, UnitPrice = 2, UnitsInStock = 4, Total = 35, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
empTree.Add(new Product { ProductName = “C”, Category = “O”, UnitPrice = 112, UnitsInStock = 3, Total = 34, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
empTree.Add(new Product { ProductName = “D”, Category = “O”, UnitPrice = 112, UnitsInStock = 0, Total = 33, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
empTree.Add(new Product { ProductName = “E”, Category = “O”, UnitPrice = 1112, UnitsInStock = 2, Total = 32, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
empTree.Add(new Product { ProductName = “F”, Category = “O”, UnitPrice = 11112, UnitsInStock = 0, Total = 31, OrderDate = new DateTime(2005, 1, 1), Id = 1 });

List l = new List();
l.Add(new Customer { CompanyName = “A”, Region = “R1”, UnitsInStock = 1, Orders = empTree, CustomerId = 0 });
l.Add(new Customer { CompanyName = “B”, Region = “R2”, UnitsInStock = 2, Orders = empTree, CustomerId = 1 });
l.Add(new Customer { CompanyName = “C”, Region = “R3”, UnitsInStock = 3, Orders = empTree, CustomerId = 2 });
l.Add(new Customer { CompanyName = “D”, Region = “R4”, UnitsInStock = 4, Orders = empTree, CustomerId = 3 });
l.Add(new Customer { CompanyName = “E”, Region = “R5”, UnitsInStock = 5, Orders = empTree, CustomerId = 4 });
return l;
}

}
class Customer : IComparable {
public string CompanyName { get; set; }
public string Region { get; set; }
public List Orders { get; set; }
public int UnitsInStock { get; set; }
public int CustomerId { get; set; }

public override string ToString() {
return String.Format(“Id: {0}, Name: {1}, Region: {3}”, this.CustomerId, this.CompanyName, this.Region);
}
int IComparable.CompareTo(Customer other) {
if (other == null)
return 1;

if (this.CustomerId > other.CustomerId)
return 1;

if (this.CustomerId < other.CustomerId) return -1; return 0; } } class Product : IComparable {
public string ProductName { get; set; }
public string Category { get; set; }
public int UnitPrice { get; set; }
public int UnitsInStock { get; set; }
public int Total { get; set; }
public DateTime OrderDate { get; set; }
public int Id { get; set; }

public override string ToString() {
return String.Format(“Id: {0}, Name: {1} , Category: {3}”, this.Id, this.ProductName, this.Category);
}
int IComparable.CompareTo(Product other) {
if (other == null)
return 1;
if (this.Id > other.Id)
return 1;

if (this.Id < other.Id) return -1; return 0; } } [/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, 8, 6, 7, 2, 0 };

        int oddNumbers = numbers.Count(n => n % 2 == 1);

        Console.WriteLine("There are {0} odd numbers in the list.", oddNumbers);
    }
}

    

   
 

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

public class MainClass {
    public static void Main() {
        int[] factorsOf300 = { 2, 2, 3, 5, 5 };

        int uniqueFactors = factorsOf300.Distinct().Count();

        Console.WriteLine("There are {0} unique factors of 300.", uniqueFactors);
    }
}