1. What is C#?
C# is an object oriented, type safe and managed language that is compiled by .Net framework to generate Microsoft Intermediate Language.
2. What are the types of comment in C# with examples?
Single line //This is a Single line comment
/*This is a multiple line comment
We are in line 2
Last line of comment*/
/// summary;
/// Set error message for multilingual language.
/// summary
3. Can multiple catch blocks be executed?
No, Multiple catch blocks can’t be executed. Once the proper catch code executed, the control is transferred to the finally block and then the code that follows the finally block gets executed.
4. 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. 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.
5. 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.
6. Define Constructors?
A constructor is a member function in a 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.
7. 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 Array of arrays.
8. 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.
9. What is the use of using statement in C#?
The using block is used to obtain a resource and use it and then automatically dispose of when the execution of block completed.
10. What is serialization?
When we want to transport an object through network then we have to convert the object into a stream of bytes. The process of converting an object into a stream of bytes is called Serialization. For an object to be serializable, it should inherit ISerialize Interface.
De-serialization is the reverse process of creating an object from a stream of bytes.
De-serialization is the reverse process of creating an object from a stream of bytes.
11. Can “this” be used 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.
12. What is difference between constants and read-only?
Constant variables are declared and initialized at compile time. The value can’t be changed after wards. Read-only variables will be initialized only from the Static constructor of the class. Read only is used only when we want to assign the value at run time.
13. What is an interface class?
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.
14. What are value types and reference types?
Value types are stored in the Stack whereas reference types stored on heap.
Value types:
Value types:
Reference Types:
15. 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 be set at design time. We can easily add custom controls to Multiple Applications (If Shared Dlls), 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.
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.
16. 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.
17. 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.
18. 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. An arraylist is similar to an array but it doesn’t have a fixed size.
19. Can a private virtual method be overridden?
No, because they are not accessible outside the class.
20. Describe the accessibility modifier “protected internal”.
Protected Internal variables/methods are accessible within the same assembly and also from the classes that are derived from this parent class.
21. What are the differences between System.String and 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 concept of a mutable string where a variety of operations can be performed without allocation separate memory location for the modified string.
22. 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 the methods perform a shallow copy.
23. How can we sort the elements of the array in descending order?
Using Sort() methods followed by Reverse() method.
24. Write down the C# syntax to catch exception?
To catch an exception, we use try catch blocks. Catch block can have parameter of system.Exception type.
Another
1. What is object-oriented programming (OOP) Language?
Object-oriented programming (OOP) is a programming language model organized around objects rather than "actions" and data rather than logic. Historically, a program has been viewed as a logical procedure that takes input data, processes it, and produces output data.
2. Explain about C# Language.
C# is a OOPs language, .net framework use to compiled it, to generate machine code.
3. Types of comments in C#?
Single line comments
// for single line comments
Multiple line comments
/* for multi line comments */
XML tags comments
/// XML tags displayed in a code comment
4. Top reason to use C# language?
Modern, general-purpose programming language
Object oriented.
Component oriented.
Easy to learn.
Structured language.
It produces efficient programs.
It can be compiled on a variety of computer platforms.
Part of .Net Framework.
5. feature of C# language?
Boolean Conditions
Automatic Garbage Collection
Standard Library
Assembly Versioning
Properties and Events
Delegates and Events Management
Easy-to-use Generics
Indexers
Conditional Compilation
Simple Multithreading
LINQ and Lambda Expressions
Integration with Windows
6. What is a Class?
a set or category of things having some property or attribute in common and differentiated from others by kind, type, or quality.
7. What is object?
Objects are created from Classes, in C#, is an instance of a class that is created dynamically. Object is also a keyword that is an alias for the predefined type System.
8. What is Constructors, explain with syntax
A is special method of the class that will be automatically invoked when an instance of the class is created is called as constructor.
Constructors are mainly used to initialize private fields of the class while creating an instance for the class.
When you are not creating a constructor in the class, then compiler will automatically create a default constructor in the class that initializes all numeric fields in the class to zero and all string and object fields to null.
Syntax.
[Access Modifier] ClassName([Parameters])
{
}
9. Types of Constructors
Basically constructors are 5 types those are
Default Constructor
Parameterized Constructor
Copy Constructor
Static Constructor
Private Constructor
10. index value of the first element in an array?
first element is 0 (zero). In a Array.
11. Different between method overriding and method overloading?
In Overriding methods it will create two or more methods with same name and same parameter in different classes.
while Overloading it will create more then one method with same name but different parameter in same class.
12. Explain use of Abstract and Sealed Classes in C#?
The abstract keyword enables you to create classes and class members that are incomplete and must be implemented in a derived class.
The sealed keyword enables you to prevent the inheritance of a class or certain class members that were previously marked virtual.
13. What is Static Classes?
A static class is basically the same as a non-static class, but there is one difference: a static class cannot be instantiated.
In other words, you cannot use the new keyword to create a variable of the class type. Because there is no instance variable, you access the members of a static class by using the class name itself.
14. Explain Static Class Members.
A non-static class can contain static methods, fields, properties, or events.
The static member is callable on a class even when no instance of the class has been created. The static member is always accessed by the class name, not the instance name. Only one copy of a static member exists, regardless of how many instances of the class are created.
Static methods and properties cannot access non-static fields and events in their containing type, and they cannot access an instance variable of any object unless it is explicitly passed in a method parameter.
15. Which are Access Modifiers available in C#?
All types and type members have an accessibility level, which controls whether they can be used from other code in your assembly or other assemblies.
You can use the following access modifiers to specify the accessibility of a type or member when you declare it:
public: The type or member can be accessed by any other code in the same assembly or another assembly that references it.
private: The type or member can be accessed only by code in the same class or struct.
protected: The type or member can be accessed only by code in the same class or struct, or in a class that is derived from that class.
internal: The type or member can be accessed by any code in the same assembly, but not from another assembly.
16. Data Types in C#?
bool, byte , char, decimal , double, float, int, long, sbyte , short, uint, ulong, ushort.
More question coming soon.. we are updating our list of ques and answer... :)
keep wait and watch for few days.
Another
1. What is object-oriented programming (OOP) Language?
Object-oriented programming (OOP) is a programming language model organized around objects rather than "actions" and data rather than logic. Historically, a program has been viewed as a logical procedure that takes input data, processes it, and produces output data.
2. Explain about C# Language.
C# is a OOPs language, .net framework use to compiled it, to generate machine code.
3. Types of comments in C#?
Single line comments
// for single line comments
Multiple line comments
/* for multi line comments */
XML tags comments
/// XML tags displayed in a code comment
4. Top reason to use C# language?
Modern, general-purpose programming language
Object oriented.
Component oriented.
Easy to learn.
Structured language.
It produces efficient programs.
It can be compiled on a variety of computer platforms.
Part of .Net Framework.
5. feature of C# language?
Boolean Conditions
Automatic Garbage Collection
Standard Library
Assembly Versioning
Properties and Events
Delegates and Events Management
Easy-to-use Generics
Indexers
Conditional Compilation
Simple Multithreading
LINQ and Lambda Expressions
Integration with Windows
a set or category of things having some property or attribute in common and differentiated from others by kind, type, or quality.
7. What is object?
Objects are created from Classes, in C#, is an instance of a class that is created dynamically. Object is also a keyword that is an alias for the predefined type System.
8. What is Constructors, explain with syntax
A is special method of the class that will be automatically invoked when an instance of the class is created is called as constructor.
Constructors are mainly used to initialize private fields of the class while creating an instance for the class.
When you are not creating a constructor in the class, then compiler will automatically create a default constructor in the class that initializes all numeric fields in the class to zero and all string and object fields to null.
Syntax.
[Access Modifier] ClassName([Parameters])
{
}
9. Types of Constructors
Basically constructors are 5 types those are
Default Constructor
Parameterized Constructor
Copy Constructor
Static Constructor
Private Constructor
10. index value of the first element in an array?
first element is 0 (zero). In a Array.
In Overriding methods it will create two or more methods with same name and same parameter in different classes.
while Overloading it will create more then one method with same name but different parameter in same class.
12. Explain use of Abstract and Sealed Classes in C#?
The abstract keyword enables you to create classes and class members that are incomplete and must be implemented in a derived class.
The sealed keyword enables you to prevent the inheritance of a class or certain class members that were previously marked virtual.
13. What is Static Classes?
A static class is basically the same as a non-static class, but there is one difference: a static class cannot be instantiated.
In other words, you cannot use the new keyword to create a variable of the class type. Because there is no instance variable, you access the members of a static class by using the class name itself.
14. Explain Static Class Members.
A non-static class can contain static methods, fields, properties, or events.
The static member is callable on a class even when no instance of the class has been created. The static member is always accessed by the class name, not the instance name. Only one copy of a static member exists, regardless of how many instances of the class are created.
Static methods and properties cannot access non-static fields and events in their containing type, and they cannot access an instance variable of any object unless it is explicitly passed in a method parameter.
15. Which are Access Modifiers available in C#?
All types and type members have an accessibility level, which controls whether they can be used from other code in your assembly or other assemblies.
You can use the following access modifiers to specify the accessibility of a type or member when you declare it:
public: The type or member can be accessed by any other code in the same assembly or another assembly that references it.
private: The type or member can be accessed only by code in the same class or struct.
protected: The type or member can be accessed only by code in the same class or struct, or in a class that is derived from that class.
internal: The type or member can be accessed by any code in the same assembly, but not from another assembly.
16. Data Types in C#?
bool, byte , char, decimal , double, float, int, long, sbyte , short, uint, ulong, ushort.
More question coming soon.. we are updating our list of ques and answer... :)
keep wait and watch for few days.
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