C#

Question 1

sealed

Answer 1

prevents a class from being inherited

Question 2

private

Answer 2

The code is only accessible within the same class

Question 3

public

Answer 3

The code is accessible for all classes

Question 4

protected

Answer 4

The code is accessible within the same class, or in a class that is inherited from that class.

Question 5

internal

Answer 5

The code is only accessible within its own assembly, but not from another assembly.

Question 6

static

Answer 6

The method belongs to the Program class and not an object of the Program class.

Question 7

void

Answer 7

The method does not have a return value.

Question 8

properties

Answer 8

A property is like a combination of a variable and a method, and it has two methods: a get and a set method.

Question 9

field

Answer 9

A variable declared directly in a class. Best practice to start name with lower case letter.

Question 10

Properties and fields naming convention

Answer 10

Best practice to start name of a Property an with uppercase letter and the name of a field with a lower case letter.

Ex:
class Person {
private string name; // field

  public string Name   // property
  {
    get { return name; }   // get method
    set { name = value; }  // set method
  }
}

Question 11

Method Overloading

Answer 11

With method overloading, multiple methods can have the same name with different parameters.

Ex:
int MyMethod(int x)
float MyMethod(float x)
double MyMethod(double x, double y)

Question 12

virtual

Answer 12

Indicates that a class member can be overridden by an inherited class.

Question 13

override

Answer 13

Indicates that a class member will override a virtual class member from the parent class.

Question 14

class member

Answer 14

Fields or methods within a class.

Question 15

Abstract class

Answer 15

A restricted class that cannot be used to create objects (to access it, it must be inherited from another class).

Question 16

Abstract method

Answer 16

A method that can only be used in an abstract class. It does not have a body. The body is provided by the derived class (inherited from).

Question 17

interface

Answer 17

An interface is a completely “abstract class”, which can only contain abstract methods and properties (with empty bodies).

By default, members of an interface are abstract and public.

Question 18

interface naming convention

Answer 18

It is considered good practice to start with the letter “I” at the beginning of an interface, as it makes it easier for yourself and others to remember that it is an interface and not a class.

Question 19

enum

Answer 19

An enum is a special “class” that represents a group of constants (unchangeable/read-only variables).

To create an enum, use the enum keyword (instead of class or interface), and separate the enum items with a comma: