Answer Posted / m.shanmuga sundaram

Definition:
***********
Functions that are triggered when an associated event
happens.

example
*******

a) In C language function pointer is used as a callback
functions.

b) In C++ virtual function are used as a callback function.

c) In c# delegate keyword is used to create a call back
function.

example in c#
*************

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

namespace ConsoleApplication1
{
class Program
{
public delegate int execute(int a, int
b); //declare a delegate method

static void Main(string[] args)
{
Program p = new Program();

execute ex = new execute(p.add);
Console.WriteLine(ex(2,3)); //add method is
executed

ex = new execute(p.subtract);
Console.WriteLine(ex(2, 3)); //subtract method
is executed
}

public int add(int a, int b)
{
return (a + b);
}

public int subtract(int a, int b)
{
return (a - b);
}
}
}

Can delegates be used as callbacks?

910

---

Write the syntax for catching an exception in c#?

887

---

What does question mark mean in c#?

990

---

How many types of interface are there in c#?

987

---

What is a function c#?

974

---

Why do we use virtual methods in c#?

960

---

Does constructor return any value in c#?

955

---

What is gridview c#?

905

---

What is difference between an reference type and value type in C#?

1057

---

What is monitor in C#?

1017

---

What is the default value of object in c#?

929

---

Can property be private in c#?

886

---

What is the purpose of escape sequence?

1022

---

What is multicast delegate in c# ?

1044

---

State whether it is true to test a Web service you must create a windows application or Web application to consume this service or not?

945

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