A Journey to Lambda

When i first hear this world lambda i was in my 6th or 7th standard (well in reality i don't remember when so apprx). it was relatively a Mathematics term. Then i get older (not that much) then i start to learn Programming. I was learning C# and i hear it again Lambda. Now how the hell lambda came back to Programming so i decided to learn about it so here it is my journey to Lambda.

Part 1 : Delegates

It all start when Microsoft decide to put Delegates in C#. Well some of you might remember pointer to function concept in your C++ classes. Microsoft decided to put the same functionality in the name of delegates (Well actually delegates do much more then that).

1. here we create a delegate

public delegate void del(string msg);

2. We create methods with similar signature

public static void fun(string message)

{

Console.WriteLine(message);

}

3. and assign that delegate's handler to the function

del handler = fun;

4. next step is easy we just pass the required parameters to handler and it will execute automatically

handler("Hello World");

In Totality Code if we create a Console Application it will looks like this

public delegate void del(string msg);

public static void fun(string message)

{

Console.WriteLine(message);

}

static void Main(string[] args)

{

del handler = fun;

handler("Hello World");

Console.ReadKey();

}

Here is the output

First when i learn about this Concept i thought what the hell is that. Why would i assign my function to a delegate's handler and then use that to execute it. I mean i can directly execute my own function it's look like a stupid thing to me to do such kind of thing but actually i was wrong.

I can assign multiple function to the same delegate's handler and execute them simultaneously. just like that.

5. So to do this let's create another function.

public static void fun2(string abc)

{

Console.WriteLine("ABCD");

}

6. Assign this as well to the handler

handler += fun2;

Note : be Careful when i assign second function i had used += instead = operator.

now execute the same code

Some of you still might be thinking Ok we can call Multiple methods with the single call but what is the benefit. see the following code

public delegate void delWriter(string msg);

public static void WriteToConsole(string message)

{

Console.WriteLine(message);

}

public static void WriteToFile(string abc)

{

//Some file handling Code implementation here

//....

//...

//..

}

public static void WriteToDatabase(string abc)

{

//Some database handling Code implementation here

//....

//...

//..

}

static void Main(string[] args)

{

del handler = WriteToConsole;

handler += WriteToFile;

handler += WriteToDatabase;

handler("Hello World");

Console.ReadKey();

}

Here the implementation says that i can write to the Screen as well as on the File and the database at the same time.

Plus i get one more benefit since all the code is in different-2 functions i can easily modify them and it will not affect the other code instead of creating a long method which can be difficult to maintain (you see i am handling difficult Database, File Handling, and Console Writing operations, just kidding!)

Our story will remain to be continued...

till then Au Revoir.

A Journey to Lambda