demonstrates a custom constructor function for a structure


   

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa

Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
//  tm2.cs - demonstrates a custom constructor function for a structure
//           Compile this program using the following command line:
//               D:>csc tm2.cs
//
namespace nsStructure
{
    using System;
    using System.Globalization;
    struct tm
    {
        public tm (DateTime tmVal)
        {
            tm_sec = tmVal.Second;
            tm_min = tmVal.Minute;
            tm_hour = tmVal.Hour;
            tm_mday = tmVal.Day;
            tm_mon = tmVal.Month - 1;
            tm_year = tmVal.Year - 1900;
            tm_wday = (int) tmVal.DayOfWeek;
            tm_yday = tmVal.DayOfYear;
            TimeZone tz = TimeZone.CurrentTimeZone;
            tm_isdst = tz.IsDaylightSavingTime (tmVal) == true ? 1 : 0;
        }
        public int tm_sec;       // Seconds after the minute
        public int tm_min;       // Minutes after the hour 
        public int tm_hour;      // Hours since midnight
        public int tm_mday;      // The day of the month
        public int tm_mon;       // The month (January = 0)
        public int tm_year;      // The year (00 = 1900)
        public int tm_wday;      // The day of the week (Sunday = 0)
        public int tm_yday;      // The day of the year (Jan. 1 = 1)
        public int tm_isdst;     // Flag to indicate if DST is in effect
        public override string ToString()
        {
            const string wDays = "SunMonTueWedThuFriSat";
            const string months = "JanFebMarAprMayJunJulAugSepOctNovDec";
            return (String.Format ("{0} {1} {2,2:00} " + 
                            "{3,2:00}:{4,2:00}:{5,2:00} {6}
", 
                             wDays.Substring (3 * tm_wday, 3),
                             months.Substring (3 * tm_mon, 3),
                             tm_mday, tm_hour, tm_min,
                             tm_sec, tm_year + 1900));
        }
    }
    public class tm2Demo
    {
        static public void Main()
        {
            DateTime timeVal = DateTime.Now;
            tm tmNow = new tm (timeVal);
            Console.WriteLine (tmNow);
        }
    }
}


           
          


Structures are good when grouping data


   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Structures are good when grouping data. 
 
using System; 
 
// Define a packet structure. 
struct PacketHeader { 
  public uint packNum; // packet number 
  public ushort packLen; // length of packet 
} 
 
// Use PacketHeader to create an e-commerce transaction record. 
class Transaction { 
  static uint transacNum = 0; 
 
  PacketHeader ph;  // incorporate PacketHeader into Transaction 
  string accountNum; 
  double amount; 
 
  public Transaction(string acc, double val) { 
   // create packet header 
    ph.packNum = transacNum++;  
    ph.packLen = 512;  // arbitrary length 
 
    accountNum = acc; 
    amount = val; 
  } 
 
  // Simulate a transaction. 
  public void sendTransaction() { 
    Console.WriteLine("Packet #: " + ph.packNum + 
                      ", Length: " + ph.packLen + 
                      ",
    Account #: " + accountNum + 
                      ", Amount: {0:C}
", amount); 
  } 
} 
 
// Demonstrate Packet 
public class PacketDemo { 
  public static void Main() { 
    Transaction t = new Transaction("31243", -100.12); 
    Transaction t2 = new Transaction("AB4655", 345.25); 
    Transaction t3 = new Transaction("8475-09", 9800.00); 
 
    t.sendTransaction(); 
    t2.sendTransaction(); 
    t3.sendTransaction(); 
  } 
}


           
          


Copy a struct


   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Copy a struct. 
 
using System; 
 
// Define a structure. 
struct MyStruct { 
  public int x; 
} 
 
// Demonstrate structure assignment. 
public class StructAssignment { 
  public static void Main() { 
    MyStruct a; 
    MyStruct b; 
 
    a.x = 10; 
    b.x = 20; 
 
    Console.WriteLine("a.x {0}, b.x {1}", a.x, b.x); 
 
    a = b; 
    b.x = 30; 
 
    Console.WriteLine("a.x {0}, b.x {1}", a.x, b.x); 
  } 
}


           
          


Demonstrate a structure


   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Demonstrate a structure. 
 
using System; 
 
// Define a structure. 
struct Book { 
  public string author; 
  public string title; 
  public int copyright; 
 
  public Book(string a, string t, int c) { 
    author = a; 
    title = t; 
    copyright = c; 
  } 
} 
 
// Demonstrate Book structure. 
public class StructDemo1 { 
  public static void Main() { 
    Book book1 = new Book("Herb Schildt", 
                          "C# A Beginner's Guide", 
                          2001); // explicit constructor 
 
    Book book2 = new Book(); // default constructor 
    Book book3; // no constructor 
 
    Console.WriteLine(book1.title + " by " + book1.author + 
                      ", (c) " + book1.copyright); 
    Console.WriteLine(); 
 
    if(book2.title == null) 
      Console.WriteLine("book2.title is null."); 
    // now, give book2 some info 
    book2.title = "Brave New World"; 
    book2.author = "Aldous Huxley"; 
    book2.copyright = 1932; 
    Console.Write("book2 now contains: "); 
    Console.WriteLine(book2.title + " by " + book2.author + 
                      ", (c) " + book2.copyright); 
 
    Console.WriteLine(); 
 
// Console.WriteLine(book3.title); // error, must initialize first 
    book3.title = "Red Storm Rising"; 
 
    Console.WriteLine(book3.title); // now OK 
  } 
}


           
          


Define struct and use it

   

/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 */
using System;

namespace Client.Chapter_3___Structs__Enums__Arrays_and_Classes
{
  public struct MyStruct
  {
    public int MyInt;
    public long MyLong;
    public string MyString;
  }
  public class StructsChapter_3___Structs__Enums__Arrays_and_Classes
  {
    static void Main(string[] args)
    {
      MyStruct TheStruct;

      TheStruct.MyInt = 0;
      TheStruct.MyLong = 0;
      TheStruct.MyString = "Hello World";
    }
  }
}

           
          


Structs And Enums

   
 

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

struct Date {
    public Date(int ccyy, Month mm, int dd) {
        this.year = ccyy - 1900;
        this.month = mm;
        this.day = dd - 1;
    }

    public override string ToString() {
        return this.month + " " + (this.day + 1) + " " + (this.year + 1900);
    }

    private int year;
    private Month month;
    private int day;
}


enum Month {
    January, February, March, April,
    May, June, July, August,
    September, October, November, December
}
class Program {
    static void Entrance() {
        Month first = Month.December;
        Console.WriteLine(first);
        first++;
        Console.WriteLine(first);

        Date defaultDate = new Date();
        Console.WriteLine(defaultDate);

        Date halloween = new Date(2008, Month.October, 31);
        Console.WriteLine(halloween);
    }

    static void Main() {
        try {
            Entrance();
        } catch (Exception ex) {
            Console.WriteLine(ex.Message);
        }
    }
}

    


Use static method to initialize field

   
 
using System;

internal class MyClass {
    public int iField1 = FuncA();
    public int iField2 = FuncC();
    public int iField3 = FuncB();

    public static int FuncA() {
        Console.WriteLine("MyClass.FuncA");
        return 0;
    }

    public static int FuncB() {
        Console.WriteLine("MyClass.FuncB");
        return 1;
    }

    public static int FuncC() {
        Console.WriteLine("MyClass.FuncC");
        return 2;
    }
}

public class Starter {
    public static void Main() {
        MyClass obj = new MyClass();
    }
}