C# .NET Basic Interview Questions

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1) A local variable

a) Can be used anywhere in the program

b)  Is declared within a method - correct answer

c) Must accept a class

d) Represent a class object

2) An instance variable

a)   is an object of a class

b) represents an attribute of an object - correct answer

c) is a method of a class

d) a and c

3) Private Button print = new button();

a) creates a button control

b) initializes a button control

c)   instantiates button control

d) a and b

e)  a and c - correct answer

4) An instance method

a)  Represents the behavior of an object - correct answer

b) Represents the attribute of an object

c) Represents another class

d) a and b

5) A Constructor

a) is used to create objects

b) must have the same name as the class it is declared within

c) maybe overloaded

d) b and c

e)  all of the above - correct answer

6) class Test: Form { }

a) Creates the class Test : Form

b)  Creates the class Test that inherits the class Form - correct answer

c) Creates the class form that inherits the class Test

d) a and b

7) A variable declared inside a method is called a________variable

a) Static

b) Private

c)  Local - correct answer

d) Serial

e) b and d

8) Defining two methods with the same name but with different parameters is called.

a) Loading

b)  Overloading - correct answer

c) Multiplexing

d) Duplexing

9) Find any errors in the following BankAccount constructor: Public int BankAccount() { balance = 0; }

a) Name

b) Formal parameters

c)  Return type - correct answer

d) No errors

10) In the body of a method, C# uses the variable named_____to refer to the current object whose method is being invoked.

a) call

b)  this - correct answer

c) do

d) that

11) String mystring; Creates a(n)

a) Class

b) Constructor

c)  Object - correct answer

d) a and b

12) An Event is

a)  The result of a users action - correct answer

b) result of a party

c) code to force users action

13) A delegate defines

a) a Wahsington representative

b)  a class that encapsulates methods - correct answer

c) a means of passing arrays into methods

d) a substitue for an inherited method

14) Is it possible to pass methods as arguments for other methods without modification.

a)  True - correct answer

b) False

15) All interfaces must contain IDrivable

a)  True

b) False - correct answer

16) What is the proper header for a class that intends to use an interface.

a) class MyClass IFace

b) class MyClass ; IFace

c)  class MyClass : IFace - correct answer

d) class MyCalss {IFace}

e) class MyCalss(IFace)

17) In order for a class to use an interface, it must

a) inherit the properties of the interface

b) contain the same methods as the interface

c) create an interface objects

d)  a and b

e) all of the above - correct answer

18) Every class directly or indirectly extends the______class.

a)  System

b) Object - correct answer

c) Drawing

d) Console

19) The concept of composition specifies that you can.

a) Compose good code with C#

b) Compose C# projects with different objects - correct answer

d) Reduce errors by remaining composed during programming

e)  all of the above

20) Polymorphism occurs when the methods of the child class.

a) Override the parent class methods but maintain the implementation

b)  Maintain the same return type and arguments as the parent class, but implement it differently - correct answer

c) Have different return types and arguments than the parent class

d) Are Virtual

21) To output the value of multidimensional array, Console.WriteLines(___)

a)  myArray[1][3]; - correct answer

b) myArray[1.3];

c) myArray{1}{3};

d) myArray(1),(3);

22) All methods in an abstract base class must be declared abstract.

a)  True

b) False - correct answer

23) Methods that are declared abstract in the base class must show implementation at the time of declaration.

a) True

b)  False - correct answer

24) The code public class B : A { }

a) Defines a class that inherits all the methods of A

b)  Defines a class that inherits the public and protected methods of A only - correct answer

c) Errors

d) a and b

25) Assuming that public class B : A { public B(int i) :base(i) { } } compiles and runs correctly, what can we conclude about the constructors in the class A?

a) One constructor takes an argument of type i

b) There is only a default constructor

c)  One constructor takes an arguments of the type int - correct answer

d) a and b

26) Classes declared with the sealed keyword cannot be base class.

a)  True - correct answer

b) False

27) A method_____an exception when that method detects that a problem has occured.

a) Trys

b) Catches

c)  Throws - correct answer

d) a and b

28) Exception objects are derived from the class.

a) Try

b) Catch

c)  Exception - correct answer

d) Event

e) System

29) An abstract class

a) may contain instance variables

b) may contain constructors

c)  may extend another class

d) a and b

e) all of the above - correct answer

30) A____block enclose the code that could throw an exception.

a)  Try - correct answer

b) Catch

c) Exception

d) Error

e) a and b

31) A Thread is:

a) an object that allows computer multitasking - correct answer

b) an object that wraps itself with other threads

c)  a deprecated object that is no longer used

32) Synchronization is:

a)  the delaying of a thread until there is sufficient memory and work to keep it up

b) making every thread start and end at the same time

c) make each thread do the same thing

d) have each thread start at the same time but not necessarily finish together

e) wait until the required resources, that are used by other threads become available - correct answer

33) In C# Thread.Sleep(time) measures time in:

a) seconds

b)  milliseconds - correct answer

c) nanoseconds

d) all of the above

34) When a thread returns from a WaitSleepJoin or Suspended state it returns to the:

a) Unstarted state

b) Stopped state

c) Started state (now considering a part of the running state) - correct answer

d)  Resume state

35) The ThreadPriority enumeration does not contain:

a) Lowest

b) Highest

c)  BelowNormal

d) None of the above - correct answer

36) The way of returning a thread from s suspended state is:

a) Pulse

b) PulseAll

c) Interrupt

d) Resume - correct answer

e)  ReStart

37) In order to lock/unlock an object use the.

a)  Lock and Unlock methods

b) Enter and Exit methods - correct answer

c) Close and Open methods

d) Close and Allow methods

38) Class String and the Char structure found in the:

a) System.Strings namespace

b)  System.Text namespace

c) System.Chars namespace

d) System namespace - correct answer

39) A String literal is a:

a) only contains one character

b) contains numbers rather than letters

c)  sequence of characters in double quotation marks - correct answer

d) contains exactly its variable name and nothing else

40) To create a string literal exclude escape sequence, use:

a) !string

b)  @string - correct answer

c) #string

d) $string

41) String indexers treat strings as:

a) binary code

b) 1 to string Length

c)  arrays of characters - correct answer

d) a character

42) If an IndexofAny method is passed an array of characters it:

a) finds the first occurrence of each letter in the string

b) searches for the first occurrence of any of the characters in the string - correct answer

c)  will search for the first occurrence of the sequence of characters

d) generates an error

43) Concatenating with strings are done with:

a) reserved words

b) method calls

c) operator overloading

d)  operator overloading and method calls - correct answer

44) If two StringBuilder objects contain the same string then

a) they represent the same meory location

b)  the are two different objects - correct answer

c) if one changes, so will the other

d) None of the above

45) The proper way to convert a string to all lowercase is:

a) String = string.ToLower(string);

b) ToLower(string);

c)  string.ToLower(); - correct answer

d) string.ToLower(string);