Trắc nghiệm kiến thức căn bản C# .NET

Trong bài này, chúng ta sẽ đến với 45 câu test về C# .NET. Với mỗi lựa chọn, hãy giải thích cho sự lựa chọn đó nha.

1) A local variable

a) Can be used anywhere in the program
b) Is declared within a method
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
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

4) An instance method

a) Represents the behavior of an object
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

6) class Test: Form { }

a) Creates the class Test : Form
b) Creates the class Test that inherits the class Form
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
d) Serial
e) b and d

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

a) Loading
b) Overloading
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
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
c) do
d) that

11) String mystring; Creates a(n)

a) Class
b) Constructor
c) Object
d) a and b

12) An Event is

a) The result of a users action
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
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
b) False

15) All interfaces must contain IDrivable

a) True

b) False

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
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

18) Every class directly or indirectly extends the______class.

a) System
b) Object
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
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
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];
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

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

a) True
b) False

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
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
d) a and b

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

a) True
b) False

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

a) Trys
b) Catches
c) Throws
d) a and b

28) Exception objects are derived from the class.

a) Try
b) Catch
c) Exception
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

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

a) Try
b) Catch
c) Exception
d) Error
e) a and b

31) A Thread is:

a) an object that allows computer multitasking
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

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

a) seconds
b) milliseconds
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)
d) Resume state

35) The ThreadPriority enumeration does not contain:

a) Lowest
b) Highest
c) BelowNormal
d) None of the above

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

a) Pulse
b) PulseAll
c) Interrupt
d) Resume
e) ReStart

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

a) Lock and Unlock methods
b) Enter and Exit methods
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

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
d) contains exactly its variable name and nothing else

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

a) !string
b) @string
c) #string
d) $string

41) String indexers treat strings as:

a) binary code
b) 1 to string Length
c) arrays of characters
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
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

44) If two StringBuilder objects contain the same string then

a) they represent the same meory location
b) the are two different objects
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();
d) string.ToLower(string);

Editor: Dương Tạ Kim Linh (Baomathethong.blogspot.com)

Author & Source: N/A