Elance C# Test Answers 2015



Which statement do you use to stop loop processing without a condition?
continue;
break;
jump;


Consider the following C# code: int x = 123; if (x) { Console.Write("The value of x is nonzero."); } What happens when it is executed?
It is invalid in C#.
Prints "The value of x is nonzero." to the screen.


What do the following two lines of code demonstrate: string Substring (int startIndex) string Substring (int startIndex, int length) ?
method reflection
method overloading
operator overloading


The default value of a reference type is...
none of these
0
unknown
null


Given the following C# statement: int[] myInts = { 5, 10, 15 }; What is the value of myInts[1]?
15
10
5


In order to create a filestream object in C#, what do you need to include in your program?
using System.Strings
#include <System.IO>
using System.IO;


Exceptions can be handled in C# with a...
none of these
ON ERROR Resume NEXT statement
try catch finally block
Throw Exception


Choose the types of members which you can have in your C# class?
fields
methods
all of these
constructors


Exceptions can be handled in Csharp with a...
Throw Exception
try catch finally block
ON ERROR Resume NEXT statement
none of these


If your Csharp class is called Cats, which statement creates an object of type Cats?
Cats myCat = new Cats();
cats myCat = new cats();
Cats myCat = new cats();


Which C# debugging tools are available to you with Visual Studio?
All of these
Breakpoints
Stepping through your code


The manifest of a C# assembly contains...
all of these
supported locales.
version information.


The purpose of the curly braces, { and }, in C#:
None of these
is to mark the beginning and end of a logical block of code.
is to mark function code to be used globally.
is to delineate the end of a statement to be executed.


What type of memory management does Csharp employ?
manual allocation
managed


Which of the following is not a built-in data type in C#?
int
single
bool
string


The keyword used to include libraries/namespaces in C# is:
include
import
use
using


Csharp provides a built in XML parser. What line is needed to use this feature?
using System.Parser
using System;
using System.Xml;
using System.Strings


C# support what types of inheritance.
Interface inheritance
Implementation inheritance
All options.


Which classes are provided in C# for writing an XML file?
XMLReader
XMLWriter
XMLCreation


Which statement is a convenient way to iterate over items in an array?
switch
for
foreach


True or false: A class can implement multiple interfaces
True
False


var x = default(DateTime); What is the expected value of "x" ?
null
1/1/0001 12:00:00 AM
0
Compiler error
Exception will be thrown


A sealed class in C# means:
that you can create objects of that class type.
that the class cannot be used for inheritance.
derived classes can override some of the class methods.


The foreach loop in C# is constructed as:
foreach (int i in collection)
there is no foreach loop in C#
foreach (collection as int i)
foreach (int i : collection)
for (int i : collection)


CSharp cannot be run without installing...
all .NET languages.
the Java Virtual Machine.
the Common Language Runtime.


What is the purpose of the following statement: ~myClass() ?
It is a constructor for myClass instances.
It is a property called myClass.
It is the destructor for myClass instances.


In C#, what would you use to output the contents of a variable to the screen?
Console.Print() method
System.Write() method
Console.Write() method


What are the access modifiers available in C#?
public, private
protected, internal, private
public, protected, internal, private
public, protected, private
public, internal, private


Which class provides the best basic thread creation and management mechanism for most tasks in Csharp?
System.Threading.ThreadPool
System.Runtime.Serialization
System.IO.Compression


The Code Document Object Model can be used for...
all of these
allowing developers to create their own code generation utilities.
developing automatic source code generators.


Which keyword would be used in a class declaration to stop the class from being inherited?
out
sealed
static
extern


What is the purpose of the ref keyword in C#?
It allows you to change the reference address of the variable.
It allows you to reference a variable value from anywhere inside of your program.
It allows you to pass a parameter to a method by reference instead of by value.


What is the result of the following expression? int x = 100 / 0;
The system will throw a DivideByZeroException more info
The system will throw a InvalidOperationException
x = NaN;
The system will throw a MathFormatException
x = null;


Where would you find the definition for the Stack<T> class?
System.Data namespace
System.Collections.Specialized namespace
System.Collections.Generic namespace


Which of the following is an example of an auto implemented property?
public string Name { get{ return m_name;} set{ m_name=value;} }
public string Name { }
public string Name { get; set; }


Which option below is an Operator?
All Options
Unary
Ternary
Binary


If you know that a method will need to be redefined in a derived class,
you should declare it as virtual in the base class.
you should declare it as partial in the base class.
you should declare it as private in the base class.


What is the keyword to create a condition in a switch statement that handles unspecified cases?
else(...)
if(...)
standard
default
finally


Can you change the value of a variable while debugging a C# application?
No, code gets "locked-down" during runtime.
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.


An Indexer in C# allows you to index a
struct
class
Both class and struct


bool test = true; string result = test ? "abc" : "def"; What is the value of result after execution?
It doesn't compile.
def
abc
abcdef
testabc


What is a jagged array in C#?
A multi-dimensional array with dimensions of various sizes.
An array of singular dimension with an unknown size.
A multi-dimensional array with dimensions of the same size.


What does if((number <= 10) && (number >= 0)) evaluate to if number is -6?
True
False


When the protected modifier is used on a class member,
no other class instances can access it.
the member can be accessed by derived class instances.
it becomes the default access for all members of the class.


Classes that can be used for reading / writing files like TextReader, StreamWriter, File can be found in which namespace?
System.IO
System.Data
System.Stream
System.Text
System.DataAnnotations


Given the following statement: public enum Days { Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday }. What is the value of Monday?
1
"Monday"
none of these
0


An interface contains signatures only for
all of these
events
methods
properties
indexers


In C#, methods with variable number of arguments:
don't exist
can be created using the "params" keyword in argument list
can be created using the "..." signs in argument list


Which of the following describes a C# interface?
An interface is the UI presented to the user in an application.
An interface allows you to define how a class will be named.
An interface contains only methods and delegates.
Interface is a keyword that allows classes to inherit from other classes.
An interface contains only the signatures of methods, delegates or events.


What is the full name of the type that is represented by keyword int?
System.Int64
Int32
System.Int32
System.Math.Int32
System.Int


A struct differs from a class in C#
in that a struct stores the value not a reference to the value.
in that a class can be stored as either a reference or a value.
in that a struct can contain implementation inheritance.


During the class definition, inheritance in C# is acomplished by putting which of the following:
":" sign
all of the answers are correct
keyword "inherits"
keyword "extends"


Which classes are provided in C# for navigating through an XML file?
XMLReader
None of these
Both XMLDocument and XMLReader
XMLDocument


Valid parameter types for Indexers in C# are...
integer
all of these
enum
string


The C# statement: using System; means...
all of these
create a namespace called system from the classes defined in this file.
import the collection of classes in the System namespace.


string is a mutable data type
True
False


Csharp provides an XML documentation comment syntax by prefacing your comment lines with...
/*
//
///


In C# the System.String.Format method is used for ....
Prettifying code snippets.
Coloring a input string with different colors to be used for text visualization.
Making the specified string wordwrapped for text visualization.
Replacing the format item in a specified string with the string representation of a corresponding object.
Automatically formatting decimals into a currency string representation. Ex: 1000 becomes $1 000


A static class in C# can only contain...
static members
both private and public members
both static and non-static members
none of these


Which of the following declares your Csharp class as an attribute?
public class myAttribute : System.Attribute
public class myAttribute as System.Attribute
public class myAttribute


What is unique about an abstract class in C#?
You can only instantiate a reference to it.
You cannot inherit another class from it.
You cannot create an instance of it.


What does the following statement do?: DateTime? startDate;
makes the variable a runtime only variable
allows you to create a reference to a value instead of a stored value
allows you to set the variable startDate equal to null


When the public modifier is used on a class,
no other classes can access it inside of your program.
it becomes the default access for all classes in your program.
the class can be accessed by external dll's.


Which keyword is needed to compile a method in Csharp which uses pointers?
static
void
unsafe


If your C# class is a static class called OutputClass, which contains public static void printMsg();, how would you call printMsg?
OutputClass oc = new OutputClass(); oc.printMsg();
OutputClass.printMsg();
Both of these


You can attach a handler to an event by using which operator?
++
+=
=
=>
->


The extern keyword is used to declare a method which is...
implemented within the current project.
implemented externally.
implemented within one of the C# System classes.


What is the full name of the base type of all the types in .NET?
System.Object
System
object
Object
System.object


Which of the following best describes this class definition? : public class Foo<T> {}
This class extends the T class
It is a generic class
None of these
This class implements the T class
It is a class which contains one or more arrays


If you are overloading methods in a class the methods must have...
none of these
the same parameter types.
the same name.
the same number of parameters.


In order for the following to compile: using (CustomClass = new CustomClass()) { } CustomClass needs to implement which interface?
IDisposable
ICustomAdapter
IUsing
Disposable
IMemoryManagement


The following line of code in C#: IEnumerable<int> aList = new List<int>();
Legal
Illegal because the constructor of List cannot be empty
Illegal because List does not implement IEnumerable interface
Illegal because it is not allowed to create an object of interface type


C# code is compiled in...
Common Intermediate Language, compiled in CPU-specific native code the first time it's executed.
x86, x64 specific native code (or both), depending on compilation options
Neutral bytecode, executed by the .Net virtual machine.


Given: var foo = 7%2; what is the value of foo?
0.035
7
3
3.5
1


In CSharp, what is the default member accessibility for a class?
public
protected
private


Reflection is used to...
discover types and methods of assemblies on a user's machine.
dynamically invoking methods on a user's machine.
viewing metadata.
all of these


In C#, if you would like to create a class across multiple files, you should precede the class definition with...
the partial keyword
the internal keyword
the public keyword


Which attribute specifies a method to run after serialization occurs?
OnSerialized
OnDeserializing
OnSerializing
OnDeserialized


How do you implement your own version of ToString() method in your class?
private override string ToString() { }
public override string ToString() { }
public override ToString() { }
public string ToString() { }
public virtual string ToString() { }


How do you catch an exception indicating that you are accessing data outside of the bounds of the array?
catch(ArrayTypeMismatchException ex)
catch(InsufficientExecutionStackException ex)
catch(ArrayIndexOutOfBounds ex)
catch(IndexOutOfRangeException ex)


Applications written in C# require the .NET framework...
all of these
to be installed on the machine running the application.
and the Visual Studio compiler to be installed on the machine running the application.


A difference between a struct and a class is that...
a struct acts like a value type.
structs support inheritance.
none of these
a struct is stored on the heap.


Which of the following is not a C# keyword?
as
in
is
of
if


In C#, a subroutine is called a ________.
Function
Method
Managed Code
Metadata


True or False? ushort is a signed integer.
False
True


Can you use pointers to manipulate memory in C#?
No, C# objects are managed by garbage collection.
Yes, but only by using the unsafe keyword.
No, it is not a feature of C#.


What happens with the following lines? #region Debug [block of code HERE] #endregion
You can visually expand or collapse the block of code.
The entire block of code is executed just in debug mode.
The entire block of code is commented.


Extension methods in C#...
are called as if they were instance methods
provide a way to add methods to existing types without modifying them
all of the answers are correct
are a special kind of static method
provide a way to add methods to existing types without new derived type


Which line is required in your Csharp application in order to use the StringBuilder class?
using System.Strings
using System.Text;
using System;


Which is an example of a C# main method?
all of these
static void Main()
static int main()
none of these


What is: #if ?
Condition
Preprocessor directive
Compiler option
Invalid syntax


What will be printed on the console when the following program is executed: public static void Main(string[] args) { bool foo = new bool(); if (foo) Console.WriteLine("True"); else Console.WriteLine("False"); }
"True" will be printed on the console
"False" will be printed on the console
A compile time error will happen because foo is not initialized
A run time error will happen because foo is not initialized


In the code below. public class Utilities : System.Web.Services.WebService { [System.Web.Services.WebMethod] public string GetTime() { return System.DateTime.Now.ToShortTimeString(); } } [System.Web.Services.WebMethod] is an example of what?
Method Setting
Attribute
WebMethod
Functional Property


In the following array instantiation: string[] names = new string[2]; , how many items can the array hold?
2
1
3
0


A struct can inherit from another struct or class.
True
False


All of the following are valid c# keywords: unchecked, extern,volatile, string, unsafe, implicit, virtual, stackalloc
False
True


What is the default visibility for members of classes and structs in C#?
protected
internal
private
public


In the following statement: string[] words = text.Split(delimiterChars); what is the function of delimiterChars?
Contains an array of characters which are to be used to delimit the string.
Contains a string which is to be split into words.
Contains an array of characters to be split into words.


C# provides an XML documentation comment syntax by prefacing your comment lines with...
<!--
///
//


From which class do you need to derive to implement a custom attribute?
System.Object
System.AttributeInfo
System.Attribute
System.Reflection.Attribute
System.AttributeUsage


C# is an object oriented language which does not offer...
classes.
simple types.
global variables.


In C#, simple types like int, char, bool etc has member functions.
false
true


The [Flags] attribute indicates that an enum is to be used as a bit field. However, the compiler does not enforce this.
false
true


When dealing with currency calculations you should always use what data type?
Int
Double
Int32
Float
Decimal


What is the purpose of the [STAThread] attribute?
The [STAThread] makes it impossible to use multiple threads in your application.
The [STAThread] makes it possible to use multiple threads in your application.
The [STAThread] marks the application to use Windows Forms components
The [STAThread] marks a thread to use the Single-Threaded COM Apartment.


Converting a value type to reference type is called....
Compilation
Boxing
Unboxing
Street magic
Typecasting


What description BEST suites the code below. var Dictionary = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
We're creating a standard dictionary object
Code wont compile
We're creating a case insensitive string dictionary


Which of the following statements about static constructors are true?
The programmer cannot specify at what point in their program a static constructor will be executed.
A static constructor cannot be called directly.
All answers are correct
A static constructor does not take access modifiers or have parameters.


The expression: var ? count = 0;
Will create an implicit integer NULLABLE variable
Will give a compile time error.
Will create a dynamic NULLABLE variable
Will give a run time error.


Which keyword would be used in the class definition if we did not want to create an instance of that class?
void
static
private
sealed


What's the best practice for enumerating all the values of a Suit enum?
foreach (string suit in Enum.GetNames(typeof(Suit))) { }
foreach (Suit suit in Enum.GetValues(typeof(Suit))) { }
C# does not allow enum enumeration.


Will the following code compile? public class CustomClass : IDisposable { }
Yes
No


The built-in string class in C# provides an immutable object which means...
that the value of the string object can be changed multiple times.
that the value of the string object can be set only once.
all of these


What does the following statement do? #error Type Mismatch
Generates an exception.
Generates an error which can be caught by a try/catch block.
Generates a compiler error.


What will be the output of the following C# code: int num = 1; Console.WriteLine(NUM.ToString());
1
Compile time error
None of the above
Undefined value


What does the params method keyword do?
all of these
Allows a variable number of parameters to be used when a method is called.
Allows method parameters to be declared of any type.


What does the Obsolete attribute do when used in conjunction with a class?
All of these
It substitutes the newly specified class for the obsolete class.
It generates an error/warning when the class is used.


Consider the following statement: string str = "abcdefg";. How would get the length of str?
int strlength = str.sizeOf()
int strlength = str.Length();
int strlength = str.Length;


How do you declare a generic method that takes one parameter which must be a value type?
public void Test<T>(T t) where T : struct { ... }
public void Test<T>(T t) T is struct { ... }
public void Test<T : struct>(T t) { ... }
public void Test<struct T>(T t) { ... }


Which C# statement is equivalent to this: int myInt = new int(); ?
int myInt;
int myInt = 0;
int myInt = NULL;


Proper way of defining an extension method for a string class in C# is:
public static int WordCount(String, String str)
public static int WordCount(String str) : this String
public static int WordCount(this String str)
public static int String.WordCount(String str)
public static int WordCount(String str) : String


True or False: We can create a sealed abstract class in c#.
False
True


Can Abstract class support constructors ?
yes
no
partially


int[] myArray = new int[10]; What will be the value of myArray[1]?
null
A null reference exception woulde be thrown unless myArray[1] is first initialized to a value.
10
0


What is the result of the following code? var a = 3; a = "hello"; var b = a; Console.WriteLine(b);
A run-time error
It outputs "hello"
A compilation error
It outputs "3"


Consider the following code: static void Set(ref object value) { value = "a string"; } static void Main(string[] args) { object value = 2; Set(ref value); } After the call to "Set", what will the value in "value" be?
2
It won't compile.
"a string"


The primary expression for initializing an anonymous object in C# is in the form of:
new {...}
None of the choices, strongly typed languages cannot support anonymous objects
new T(...)
new T(...){...}


Which of the following is NOT a value type?
System.Int32
System.Char
System.Boolean
System.DateTime
System.String


Are bool and Boolean equivalent?
No, bool is a value type and Boolean is a reference type
No, Boolean doesn't exist in C#
Yes


What is the keyword 'extends' used for?
is used to extend the functionality of an existing class
'extends' keyword does not exist
is used to declare an implicit user-defined type conversion operator
is used to access members of the base class from within a derived class


What does this program output? public class Program { struct Thing { public string Color { get; set; } } public static void Main(params string[] args) { Thing one = new Thing { Color = "Red" }; Thing two = new Thing { Color = "Green" }; two = one; two.Color = "Blue"; Console.WriteLine(one.Color); } }
Red
Green
Yellow
Magenta
Blue


What is the purpose of [Flags] attribute?
It does not exist in C#
Mark a class as obsolete.
Add metadata on elements, for documentation.
Allow values combination for enumeration (enums)


Anonymous functions can see the local variables of the sourrounding methods.
False.
True.


Default DateTime.MinValue is "1/1/0001 12:00:00 AM"
True
False


What will happen if the requested type conversion is not possible when using an "as" operator ?
System.InvalidCastException is thrown
null value is returned
Program will fail to compile
C# version is 2.0 or older returns NULL and newer versions throws exception


What is the main difference between ref and out parameters when being passed to a method?
Variables marked with "out" keyword cannot be readonly whereas "ref" variables can be.
"out" parameters don't have to be initialised before passing to a method, whereas "ref" parameters do.
"ref" parameters don't have to be initialised before passing to a method, whereas "out" parameters do.
They are both same in every sense of the word.
Variables marked with "ref" keyword cannot be readonly whereas "out" variables can be.


You need to create a custom Dictionary class, which is type safe. Which code segment should you use?
public class MyDictionary : Dictionary<string, string>
None of the listed answers
public class MyDictionary : IDictionary
public class MyDictionary {...} { Dictionary<string, string> t = new Dictionary <string, string>; MyDictionary dictionary = (MyDictionary) t; }


Given the method: static int Foo(int myInt, params int[] myInts, int myOtherInt) { if (myInt > 1) return myOtherInt; foreach (dynamic @int in myInts) myInt += @int; return myInt + myOtherInt; } What will "Foo(1, 2, 3, 4, 5)" return?
Compiler error - parameter arrays must be the last parameter specified.
15
5
10
Compiler error - The "dynamic" keyword cannot be used to assign foreach iteration variables.


Which of the following is true of calling a virtual method in a constructor:
Will call the derived method before the constructor for the derived class has run.
Will generate a runtime error.
Will generate a compiler error.
Is better than an Initialize method because it requires fewer lines of code.


In C# simple types like int, char and bool are aliases for predefined classes in the System namespace.
False - they are not classes, they are structures
True - they are aliases for predefined classes in the System namespace.


What namespaces are necessary to create a localized application?
System.Data, System.Resources.
System.Globalization, System.Resources.
System.Resources, System.Localization.


Which of the following expressions give a compile time error?
var d = new[] { 1, 1.5 , 2, 2.5, null, 4, 4.5 };
var myArray = new[,] { { "A",null, "C" }, { "A", "B","C" }, { "C", "D", "E" } };
var numbers = new[] { 1, 1.5, 2, 2.545454545454 };


If you have this in your configuration: <appSettings> <add key="SomeSetting" value="1" /> </appSettings> What does the output look like for this code: var someSetting = ConfigurationManager.AppSettings["SomeSetting"]; Console.WriteLine("SomeSetting is {0} and is of type {1}", someSetting, someSetting.GetType().Name);
SomeSetting is 1 and is of type string
SomeSetting is 1 and is of type String
SomeSetting is 1 and is of type object
SomeSetting is 1 and is of type Int32
SomeSetting is 1 and is of type int


Interfaces in C# cannot contain:
all of the answers are correct
events
implementation of methods
indexers


String a = "hello"; String b = "hello"; var answer = object.ReferenceEquals(a, b); What is the value of answer?
throws an exception
True
False
null


Consider the following code snippet: public class A {...} public class B: A {...} public class C:B {...} then from the following options, which one will give a compile time error?
A a = new B();
B b = new B();
B b= new A();
A a = new C();
C c = new C();


Which of the following is NOT reference type?
System.String
System.Exception
System.Type
System.Drawing.Point


A static member of a class is:
Something that can be accessed through an instance.
Shared by all instances of a class.
Neither of these
Both of these


In C#, "explicit" keyword is used to:
explicitly cast types
"explicit" keyword doesn't exist in C#
create user-defined type conversion operator that must be invoked with a cast
all of the answers are correct


In C#, "implicit" keyword is used to:
create user-defined type conversion operator that will not have to be called explicitly
all of the answers are correct
"implicit" keyword doesn't exist in C#
turn explicit casts into implicit ones


What does the following code do? string a = "hello"; string b = null; string c = a + b; Console.WriteLine(c);
It outputs "hello"
It outputs "a + b"
It outputs "c"
It throws a NullReferenceException
It does not compile


int a = 5; for (int i = 0; i < 3; i++) { a = a - i; } What is the value of the variable a after the code runs?
2
-1
0
1
3


True or False? Changing interfaces to base classes with virtual methods can NOT improve performance of method invocations.
True
False


You are creating a class to compare a specially formatted string. You need to implement the IComparable<string> interface. Which code segment should you use?
public bool CompareTo(object other)
public int CompareTo(string other)
public bool Equals(string other)
public int Equals(object other)


What is wrong with this code: public enum @enum : ushort { Item1 = 4096, Item2 = 8192, Item3 = 16384, Item4 = 32768, Item5 = 65536, }
Invalid token ',' in class, struct, or enum.
Everything is wrong
Constant value '65536' cannot be converted to a 'ushort'
Keyword, identifier, or string expected after verbatim specifier: @
Unexpected type declaration 'System.UInt16'


What does the following code output? ------------------------------------------------ using System; using System.Collections.Generic; public class Program { public static void Main() { var dictionary = new Dictionary<string,bool>(); bool isAlive = true; dictionary.TryGetValue("Jaberwocky", out isAlive); Console.WriteLine(isAlive); } }
It throws an exception
true
false
Jaberwocky


Polymorphism. LET: public class BaseClass { public string DoWork() { return "A"; } } public class DerivedClass : BaseClass { public new string DoWork() { return "B"; } } IF: DerivedClass B = new DerivedClass(); BaseClass A = (BaseClass)B; A.DoWork(); What's the expected output?
A
Code won't compile
B


In C# "new" keyword is used to...
create objects and invoke constructors
restrict types that might be used as arguments for a type parameter in a generic declaration
hide an inherited member from a base class member
All of the answers are correct


When can you assign a value to a readonly field?
In the field constructor.
Neither of these
In the declaration of the field.
Both of these


When comparing strings, which of the following Enum Type is utilized to specify the comparison culture and whether or not it will ignore the case of the string?
StringComparer
StringFormat
StringComparison
StringUnit


In C#, difference between "new" and "override" is:
"override" works in one-level inheritance, "new" is multilevel
"new" explicitly hides a member inherited from a base class
all of the answers are correct
"new" is used to overload a method, "override" to override


What does the @ symbol do when used in C# code?
Allows you to use reserved keywords as variable names.
Both stops string literal escape sequences being processed and allows you to use reserved keywords as variable names.
None of these
Stops string literal escape sequences being processed.


C# delegates are object-oriented, type-safe, they can be created in anonymous functions, they can reference static or instance methods, and they do not know or care about the class of the referenced method.
False, there is one incorrect statement mixed with the correct ones.
True.


The following program is expected to run, and after 500 ms write "OK" and exit, but fails to do that. How would you fix this? class Test { int foo; static void Main() { var test = new Test(); new Thread(delegate() { Thread.Sleep(500); test.foo = 255; }).Start(); while (test.foo != 255) ; Console.WriteLine("OK"); } }
Wait 499 ms
Give thread a name
Make foo bool
Make foo volatile
Make Thread Priority to low


How many generations does the garbage collector in .NET employ?
5
3
4
2
1


The main reflection methods to query attributes are contained in the...
System.Reflection.GetCustomAttributes
System.Collections.Attributes
System.Reflection.MemberInfo class


Which answer is not a valid C# 4.0 variable definition?
int[,] e = new int [2, 3];
var c = new int[1];
var b = new [] { 1 };
int[] a;
int[][] d = new int[1, 2];


How many string objects are created in this piece of code: string first = "tick"; string second = first + "tech"; second += "fly";
3
1
2
5
4


What is the size of a long on a 32 bit operating system in C#?
Unsigned 32 bit integer
Signed 32 bit integer
Unsigned 64 bit integer
Signed 64 bit integer


The where condition for the generic definition should be changed to ensure that the code will compile. class MyClass<V> where V :class, IComparable { public void foo() { V aClass = new V(); } } class Program { public static void Main(string[] args) { } } How should the where condition be changed?
Remove IComparable from the generic where condition
Remove "class" from the generic where condition
Add "new()" as the last generic where condition
Impliment the interface IComparable. i.e define CompareTo method inside MyClass


Cast expressions that you want to implicitly convert.
True
False


Given the following code : void Main() { var x = 123; Task t = new Task(()=>{ x++; }); t.Start(); Console.WriteLine(x.ToString()); } What is the expected value of x ?
124
123 or 124 (unpredected)
123


Given the following code: var result = 7/2; what will be the value of result?
3.49999999
4
3.5
3
This code won't compile


In C#, what is the difference between: "int[,] arrayName;" and "int[][] arrayName;"
"int[][] arrayName;" is not correct declaration
"int[][] arrayName;" is multidimensional array, while "int[,] arrayName;" is jagged array (array of arrays)
"int[,] arrayName;" is not correct declaration
"int[,] arrayName;" is multidimensional array, while "int[][] arrayName;" is jagged array (array of arrays)
There is no difference, they mean the same


What is the value of Status.TiredAndHungry? public enum Status { Unknown = 0, Sick = 1, Tired = 2, Hungry = 4, TiredAndHungry = Tired | Hungry }
5
3
6
4
This does not compile


Given code: var foo = 7; var bar = ++foo + foo++; what is the value of bar?
17
16
15
18
14


False or True? Tuple is faster in every test than KeyValuePair except in allocation performance.
False
True


Given the C# syntax for a method, attributes modifiers return-type method-name(parameters ), what does the attribute [Conditional("DEBUG")] on a method indicate?
The method will always execute when called correctly.
The method will only execute if you compile with the debug flag.
The method can only execute if the program has defined DEBUG.


In the context of (A | B) and (A || B), the (A || B) boolean evaluation is known as what?
A "standard" evaluation
A "cross-circuit" evaluation
A "comparative" evaluation
A "short-circuit" evaluation
A "default" evaluation


What is the output of following program? class Program { public enum Colors { Red = 1, Green = 2 } private static void Main() { Colors c = 0; Console.WriteLine(c); } }
It won't compile
Prints 0 in console
Prints Red in console
Prints 1 in console


It is possible to overload the "=" operator in C#.
False
True


What is the output of Console.WriteLine(10L / 3 == 10d / 3);?
True
False
Nothing, you will get a compiler error


What is the output of following program? class Program { public enum Colors : System.Int32 { Red = 0, Green = 1 } private static void Main() { Console.WriteLine(Colors.Green); } }
Prints Green in console
Throws runtime exception
It won't compile
Prints 1 in console


var a = new { name = "Frank", age = 22.5 }; var result = a.GetType() == new { name = "Bob", age = 64.1f }.GetType(); what is the value of result?
False
True
Will not compile.


What will be the output of the following program: #define DEBUG using System; using System.Diagnostics; class Program { [Conditional("DEBUG")] public static bool Print() { Console.WriteLine("Printed"); return true; } public static void Main(string[] args) { Print(); } }
It will print "Printed" on the console
It will give a run time error because DEBUG is not correctly defined
It will give a compilation error because the conditional attribute is not valid


What is the result of following function? public bool SomeTest(){ return "i like c#".ToUpper().Equals("I LIKE C#"); }
Either true or false, depending on the current culture
False, whatever the current culture
True, whatever the current culture


What will the following program print on the console: static void Main(string[] args) { var i = typeof(void); Console.WriteLine(i.Name); }
It will print "System.Object" on the console
It will throw a run time exception
It will give a compile time error
It will print "Void" on the console


Which are not function members in a C# class?
Indexers
Fields
Operators
Destructors
Events


C# provides Finalize methods as well as destructors, unlike Java. Which of the following is true about it?
That's not true, C# doesn't provide destructors.
Finalize method cannot be directly implemented, however it is implicitly called by destructor, which can.
Destructor cannot be directly implemented, however it is implicitly called by Finalize method, which can.
Finalize method is the destructor in C#.


Polymorphism. LET: public class BaseClass { public virtual string DoWork() { return "A"; } } public class DerivedClass : BaseClass { public override string DoWork() { return "B"; } } IF: DerivedClass B = new DerivedClass(); BaseClass A = (BaseClass)B; A.DoWork(); What's the expected output?
A
B
The code won't compile


What is wrong with this code? public struct Person { public string FirstName { get; set; } public string LastName { get; set; } public Person() { } public Person(string firstName, string lastName) { this.FirstName = firstName; this.LastName = lastName; } } public struct Customer : Person { public List<Order> Orders = new List<Order>(); }
'this' object cannot be used before all of its fields are assigned to
Structs cannot contain explicit parameterless constructors
All the answers
Structs cannot inherit from other classes or structs
Structs cannot have instance field initializers


What will be the result of the following code: float f = 1.5; Console.WriteLine(f);
A runtime error.
2
A compiler error.
1.5
1


abstract class BaseClass { public abstract Color Color { get { return Color.Red; } } } sealed class Blues: BaseClass { public override Color Color { get { return Color.Blue; } } } BaseClass test = new Blues(); What is the result of test.Color ?
Blue
Compilation error
Red
null
InvalidOperationException


If A = true and B = false, how does [1.] (A | B) differ from [2.] (A || B)
In [2.], B will be evaluated, in [1.] it wont
In [1.], B will be evaluated, in [2.] it won't be.
They're the same, just different ways of writing an OR statement.
In [1.], A will be evaluated, in [2.] it wont


What is the expected output? static void Main() { object o = -10.3f; int i = (int)o; Console.WriteLine(i); }
-10
Compile time error
Runtime exception (InvalidCastException)
0
10


Assuming the local system time offset is UTC+5, what does the following program output? using System; public class Program { public static void Main() { DateTime time1 = new DateTime(2000, 1, 1, 10, 45, 0, DateTimeKind.Local); DateTime time2 = new DateTime(2000, 1, 1, 10, 45, 0, DateTimeKind.Utc); TimeSpan span = time2 - time1; Console.WriteLine(span); } }
00:05:00
-00:05:00
00:00:00


[Flags] enum Days{ None=0x0, WeekDays=0x1, WeekEnd=0x2 } Days workingDays = Days.WeekDays | Days.WeekEnd; How do you remove the Days.WeekEnd from the workingDays variable?
workingDays &= ~Days.WeekEnd;
workingDays |= !Days.WeekEnd;
workingDays &= !Days.WeekEnd;
workingDays &= ^Days.WeekEnd;
workingDays |= ~Days.WeekEnd;


Which of the following will set the process return code to 1?
Application.ExitCode = 1
Console.ErrorLevel = 1,
Environment.Result = 1
void Main() { return 1; }
Environment.ExitCode = 1


What is wrong with the following code: static class ImStatic { public event EventHandler StuffHappened; } class ReactsToStuff { public ReactsToStuff() { ImStatic.StuffHappened += React; } public void React(object sender, EventArgs args) { Console.WriteLine("Stuff happened"); } }
ReactsToStuff will never be collected by the garbage collector after it is instantiated.
Static classes cannot declare events.
None of these.
A NullReferenceException will be thrown when StuffHappened is fired if ReactsToStuff has already been collected by the garbage collector.
Instance classes cannot handle events from static classes


Can multiple catch blocks be executed?
No, once the proper catch code fires off, the control is transferred to the finally block (if there are any)
Yes, catches excute in sequential order, then the control is transferred to the finally block (if there are any)


Does return 10 as long; compile?
Yes
No, because 10 cannot be cast to long
No, because long is not a reference or nullable type
No, because there is no as operator in C#


void Disagree(ref bool? maybe) { maybe = maybe ?? true ? false : maybe; } When calling this method, the value of the reference parameter will be changed to:
true.
false.
null.
false if the previous value was true or false, true if it was null.
The logical negation of the previous value, or true if it was null.


If you would like to create a read-only property in your C# class:
Mark the set method as private.
Neither of these
Both of these
Do not implement a set method.


What does the following code do? unchecked { int i = Int32.MaxValue; int j = i; int product = i * j; Console.WriteLine(product); }
Throws an OverflowException
Outputs "1"


Which of the following operators cannot be overloaded?
=>
!=
<=
<< 
>=


True or false? Types or members that have the access modifier "protected internal" can be accessed in C# only from types that SIMULTANEOUSLY satisfy these two conditions: 1) They are derived from the containing class 2) They are in the current assembly
True
False


enum Score { Awful, Soso, Cancode } Given the enum above, which statement(s) will generate a compiler error?
Score awful = 0;
Score soso = 1;
Score cancode = (Score)2;
All of them(because enum Score: int type was not specified in declaration).
None of them(all three will compile and execute just fine).


Which of these is NOT a way to create an int array?
var b = new int[0];
var c = new [] { 0 };
var a = new int[];
int[] d = null;
var e = Array.CreateInstance(typeof(int), 1);


namespace DocGen { class Skills<T> { public void Test(T t) { } } } According to C# standards and specifications, the documentation generator ID string corresponding to "Test" method from the code above should be:
"///<Method ret="void" param="T" ns="DocGen" class="Skills" public="true"> Test </Method>"
"M:DocGen.Skills.Test(ret void, param System.Type):ContainsGenericParameters=true"
"M:DocGen.Skills.Test(T)"
"M:DocGen.Skills`1.Test(`0)"
All of them


What does the following statement do: delegate double Doubler(double x); ?
Creates a signature for the method Doubler in the delegate class.
Creates a type for the method Doubler.
Creates a method which may be called by any class.

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