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Passing parameter by value?
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Section 1
(50 cards)
Passing parameter by value?
when you call a method and pass parameter by value the value will not be changed.
How can we sort the elements of the Array in descending order?
Using Sort() methods followed by Reverse() method.
What is the difference between constants and read-only?
Constant variables are declared and initialized at compile time. The value can't be changed afterward. Read-only is used only when we want to assign the value at run time.
What's the difference between the System.Array.CopyTo() and System.Array.Clone()?
Using Clone() method, we creates a new array object containing all the elements in the original Array and using CopyTo() method. All the elements of existing array copies into another existing array. Both methods perform a shallow copy
List down the commonly used types of exceptions in .net
ArgumentException, ArgumentNullException, ArgumentOutOfRange Exception, Arithmetic Exception, DivideByZeroException ,OverflowException, IndexOutOfRange Exception ,Invalid Cast Exception ,InvalidOperation Exception, IOEndOfStream Exception, NullReferenceException, OutOfMemoryException, StackOverflowException etc.
How to use nullable types in .Net?
Value types can take either their normal values or a null value. Int? someID = null;
What's a multicast delegate?
A delegate having multiple handlers assigned to it is called multicast delegate. Each handler is assigned to a method.
What is an object?
An object is an instance of a class through which we access the methods of that class. "New" keyword is used to create an object. A class that creates an object in memory will contain the information about the methods, variables, and behavior of that class.
What happens if the inherited interfaces have conflicting method names?
Implement is up to you as the method is inside your own class. There might be a problem when the methods from different interfaces expect different data, but as far as compiler cares you're okay.
What are the different ways a method can be overloaded?
Methods can be overloaded using different data types for a parameter, different order of parameters, and different number of parameters.
What is Jagged Arrays?
The Array which has elements of type array is called jagged Array. The elements can be of different dimensions and sizes. We can also call jagged Array as an Array of arrays.
What is the difference between a Struct and a Class?
Structs are value-type variables, and classes are reference types. Structs stored on the Stack causes additional overhead but faster retrieval. Structs cannot be inherited.
What is an object pool in .NET?
An object pool is a container having objects ready to be used. It tracks the object that is currently in use, total number of objects in the pool. This reduces the overhead of creating and re-creating objects.
What is the difference between public, static, and void?
Public declared variables or methods are accessible anywhere in the application. Static declared variables or methods are globally accessible without creating an instance of the class. Static member are by default not globally accessible it depends upon the type of access modified used. The compiler stores the address of the method as the entry point and uses this information to begin execution before any objects are created. And Void is a type modifier that states that the method or variable does not return any value.
Define Constructors
A constructor is a member function ina class that has the same name as its class. The constructor is automatically invoked whenever an object class is created. It constructs the values of data members while initializing the class.
How to implement a singleton design pattern in C#?
A console application is an application that can be run in the command prompt in Windows. For any beginner on .Net, building a console application is ideally the first step, to begin with.
How do you inherit a class into other class in C#?
Colon is used as inheritance operator in C# . Just place a colon and then the class name.
What is C#?
C# is an object-oriented, type-safe, and managed language that is compiled by.Net framework to generate Microsoft Intermediate Language.
What is the difference between method overriding and methoc overloading?
In method overriding, we change the method definition in the derived class that changes the method behavior. Method overloading is creating a method with the same name within the same class having different signatures.
What is method overloading?
Method overloading is creating multiple methods with the same name with unique signatures in the same class. When we compile, the compiler uses overload resolution to determine the specific method to be invoke.
What are indexers in C# .NET?
Indexers are known as smart arrays in C#. It allows the instances of a class to be indexed in the same way as an array.
What are C# attributes and its significance?
C# provides developers a way to define declarative tags on certain entities, eg. Class, method, etc. are called attributes. The attribute's information can be retrieved at runtime using Reflection.
What is serialization?
When we want to transport an object through a network, then we have to convert the object into a stream of bytes. The process of converting an object into a stream of bytes. For an object to be serializable it should implement ISerialize Interface. Deserialization is opposite.
What are circular references?
Circular reference is situation in which two or more resources are interdependent on each other causes the lock condition and make the resources unusable.
Can a private virtual method can be overridden?
No, because they are not accessible outside the class.
Why can't you specify the accessibility modifier for methods inside the interface?
In an interface, we have virtual methods that do not have method definition. All the methods are there to be overridden in the derived class. That's why they all are public.
What's the difference between an interface and abstract class?
Interfaces have all the methods having only declaration but no definition. In an abstract class, we can have some concrete methods. In an interface class, all the methods are public. An abstract class may have private methods.
What is the base class in .net from which all the classes are derived from?
System.Object
Can we use "this" command within a static method?
We can't use 'This' in a static method because we can only use static variables/methods in a static method.
What is the difference between Finalize() and Dispose() methods?
Dispose() is called when we want for an object to release any unmanaged resources with them. On the other hand, Finalize() is used for the same purpose, but it doesn't assure the garbage collection of an object.
What are Custom Exceptions?
Sometimes there are some errors that need to be handled as per user requirements. Custom exceptions are used for them and are used defined exceptions.
Can multiple catch blocks be executed?
No, Multiple catch blocks can't be executed. Once the catch proper code executed, the control is transferred to the finally block, and then the code that follows the finally block gets executed.
How can we set the class to be inherited, but prevent the method from being over-ridden?
Declare the class as public and make the method sealed to prevent it from being overridden.
What is the use of 'using' statement in C# ?
The 'using' block is used to obtain a resource and process it and then automatically dispose of when the execution of the block completed.
What are generics in C #.NET?
Generics are used to make reusable code classes to decrease the code redundancy, increase type safety, and performance. Using generics, we can create collection classes. To create generic collection, System.Collections.Generic namespace should be used instead of classes such as ArrayList in the System.Collections namespace. Generics promotes the usage of parameterized types.
What are the differences between System.String System.Text.StringBuilder classes?
System.String is immutable. When we modify the value of a string variable, then a new memory is allocated to the new value and the previous memory allocation released. System.StringBuilder was designed to have a concept of a mutable string where a variety of operations can be performed without allocation separate memory location for the modified string.
How we can create an array with non-default values?
We can create an array with non-default values using Enumerable.Repeat.
What is an interface class? Give one example of it
An Interface is an abstract class which has only public abstract methods, and the methods only have the declaration and not the definition. These abstract methods must be implemented in the inherited classes.
What are value types and reference types?
Value types are stored in the Stack, whereas reference types stored on heap.
Give an example of removing an element from the queue
The dequeue method is used to remove an element from the queue.
What is the difference between Array and Arraylist?
In an array, we can have items of the same type only. The size of the array is fixed when compared. To an arraylist is similar to an array, but it doesn't have a fixed size.
What are Custom Control and User Control?
Custom Controls are controls generated as compiled code (Dlls), those are easier to use and can be added to toolbox. Developers can drag and drop controls to their web forms. Attributes can, at design time. We can easily add custom controls to Multiple Applications (If Shared Dlls). So, If they are private, then we can copy to dll to bin directory of web application and then add reference and can use them. User Controls are very much similar to ASP include files, and are easy to create. User controls can't be placed in the toolbox and dragged -dropped from it. They have their design and code- behind. The file extension for user controls is ascx.
What is difference between "is" and "as" operators in c#?
"is" operator is used to check the compatibility of an object with a given type, and it returns the result as Boolean. "as" operator is used for casting of an object to a type or a class.
What are delegates?
Delegates are same are function pointers in C++, but the only difference is that they are type safe, unlike function pointers. Delegates are required because they can be used to write much more generic type-safe functions.
Describe the accessibility mod ifier "protected internal"
Protected Internal variables/methods are accessible within the same assembly and also from the classes that are derived from this parent class.
What is difference between the "throw" and "throw ex" in .NET?
"Throw" statement preserves original error stack whereas "throw ex" have the stack trace from their throw point. It is always advised to use "throw" because it provides more accurate error information.
What is access modifiers
level of accessibility. Public can be accessed in entire solution. Private access modifier can be accessed only in a class it was declared. Protected access modifier can be used in the class that it was declared in and the class that inherits this class.
Write down the C# syntax to catch an exception
if every statement works in the block it will never go to catch. If even one line doesn't work in the block it will go to catch. You can have multiple catches: most specific ones will go first. The generic one will come last. If you have an error and went to the first catch it will never go to any other catches. You can have finally which will be always executed.
What are sealed classes in C#?
We create sealed classes when we want to restrict the class to be inherited. Sealed modifier used to prevent derivation from a class. If we forcefully specify a sealed class as base class, then a compile- time error occurs
What is the difference between ref & out parameters?
An argument passed as ref must be initialized before passing to the method whereas out parameter needs not to be initialized before passing to a method.
Section 2
(21 cards)