70-483 Programming in C#

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Question 1

You are developing an application that includes a class named Kiosk. The Kiosk class
includes a static property named Catalog. The Kiosk class is defined by the following code
segment. (Line numbers are included for reference only.)


You have the following requirements:
✑ Initialize the _catalog field to a Catalog instance.
✑ Initialize the _catalog field only once.
✑ Ensure that the application code acquires a lock only when the _catalog object
must be instantiated.
You need to meet the requirements.
Which three code segments should you insert in sequence at line 09? (To answer, move
the appropriate code segments from the list of code segments to the answer area and
arrange them in the correct order.)



Answer :

Explanation:

D:\Documents and Settings\useralbo\Desktop\1.jpg After taking a lock you must check once again the _catalog field to be sure that other threads didn't instantiated it in the meantime.

Question 2

You are developing an application. The application calls a method that returns an array of
integers named customerIds. You define an integer variable named customerIdToRemove
and assign a value to it. You declare an array named filteredCustomerIds.
You have the following requirements.
✑ Remove duplicate integers from the customerIds array.
✑ Sort the array in order from the highest value to the lowest value.
✑ Remove the integer value stored in the customerIdToRemove variable from the
customerIds array.
You need to create a LINQ query to meet the requirements.
Which code segment should you use?


  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D


Answer : C

Question 3

You are developing an application that includes a class named Order. The application will
store a collection of Order objects.
The collection must meet the following requirements:
✑ Internally store a key and a value for each collection item.
✑ Provide objects to iterators in ascending order based on the key.
✑ Ensure that item are accessible by zero-based index or by key.
You need to use a collection type that meets the requirements.
Which collection type should you use?

  • A. LinkedList
  • B. Queue
  • C. Array
  • D. HashTable
  • E. SortedList


Answer : E

Explanation: SortedList<TKey, TValue> - Represents a collection of key/value pairs that are sorted by key based on the associated IComparer<T> implementation. http://msdn.microsoft.com/en-us/library/ms132319.aspx

Question 4

You are developing an application by using C#.
The application includes an object that performs a long running process.
You need to ensure that the garbage collector does not release the object's resources until
the process completes.
Which garbage collector method should you use?

  • A. WaitForFullGCComplete()
  • B. SuppressFinalize()
  • C. WaitForFullGCApproach()
  • D. WaitForPendingFinalizers()


Answer : B

Question 5

You are developing an application that includes a class named BookTracker for tracking
library books. The application includes the following code segment. (Line numbers are
included for reference only.)


You need to add a user to the BookTracker instance. What should you do?

  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D


Answer : B

Question 6

You are creating an application that manages information about zoo animals. The
application includes a class named Animal and a method named Save.
The Save() method must be strongly typed. It must allow only types inherited from the
Animal class that uses a constructor that accepts no parameters.
You need to implement the Save() method.
Which code segment should you use?


  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D


Answer : C

Explanation: When you define a generic class, you can apply restrictions to the kinds of types that client code can use for type arguments when it instantiates your class. If client code tries to instantiate your class by using a type that is not allowed by a constraint, the result is a compile-time error. These restrictions are called constraints. Constraints are specified by using the where contextual keyword. http://msdn.microsoft.com/en-us/library/d5x73970.aspx

Question 7

You are creating an application that manages information about your company's products.
The application includes a class named Product and a method named Save.
The Save() method must be strongly typed. It must allow only types inherited from the
Product class that use a constructor that accepts no parameters.
You need to implement the Save() method. Which code segment should you use?


  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D


Answer : D

Explanation: When you define a generic class, you can apply restrictions to the kinds of types that client code can use for type arguments when it instantiates your class. If client code tries to instantiate your class by using a type that is not allowed by a constraint, the result is a compile-time error. These restrictions are called constraints. Constraints are specified by using the where contextual keyword. http://msdn.microsoft.com/en-us/library/d5x73970.aspx

Question 8

An application receives JSON data in the following format:


The application includes the following code segment. (Line numbers are included for
reference only.)

You need to ensure that the ConvertToName() method returns the JSON input string as a
Name object.
Which code segment should you insert at line 10?

  • A. Return ser.Desenalize (json, typeof(Name));
  • B. Return ser.ConvertToType&lt;Name>(json);
  • C. Return ser.Deserialize&lt;Name>(json);
  • D. Return ser.ConvertToType (json, typeof (Name));


Answer : C

Question 9

You are developing an application that uses several objects. The application includes the
following code segment. (Line numbers are included for reference only.)


You need to evaluate whether an object is null.
Which code segment should you insert at line 03?

  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D


Answer : D

Explanation: Use the == operator to compare values and in this case also use the null literal.

Question 10

You are developing an application by using C#. The application includes an array of
decimal values named loanAmounts. You are developing a LINQ query to return the values
from the array.
The query must return decimal values that are evenly divisible by two. The values must be
sorted from the lowest value to the highest value.
You need to ensure that the query correctly returns the decimal values.
How should you complete the relevant code? (To answer, drag the appropriate code
segments to the correct locations in the answer area. Each code segment may be used
once, more than once, or not at all. You may need to drag the split bar between panes or
scroll to view content.)




Answer :

Explanation: Box 1: from Box 2: where Box 3: orderby Box 4: ascending Box 5: select Note: In a query expression, the orderby clause causes the returned sequence or subsequence (group) to be sorted in either ascending or descending order. Examples: // Query for ascending sort. IEnumerable<string> sortAscendingQuery = from fruit in fruits orderby fruit //"ascending" is default select fruit; // Query for descending sort. IEnumerable<string> sortDescendingQuery = from w in fruits orderby w descending select w;

Question 11

You are developing a custom collection named LoanCollection for a class named Loan
class.
You need to ensure that you can process each Loan object in the LoanCollection collection
by using a foreach loop.
How should you complete the relevant code? (To answer, drag the appropriate code
segments to the correct locations in the answer area. Each code segment may be used
once, more than once, or not at all. You may need to drag the split bar between panes or
scroll to view content.)




Answer :

Question 12

You are developing an application in C#.
The application will display the temperature and the time at which the temperature was
recorded. You have the following method (line numbers are included for reference only):


You need to ensure that the message displayed in the lblMessage object shows the time
formatted according to the following requirements:
✑ The time must be formatted as hour:minute AM/PM, for example 2:00 PM.
✑ The date must be formatted as month/day/year, for example 04/21/2013.
✑ The temperature must be formatted to have two decimal places, for example 23-
45.
Which code should you insert at line 04? (To answer, select the appropriate options in the
answer area.)



Answer :

Question 13

You are developing an application. The application includes a method named ReadFile that
reads data from a file.
The ReadFile() method must meet the following requirements:
✑ It must not make changes to the data file.
✑ It must allow other processes to access the data file.
✑ It must not throw an exception if the application attempts to open a data file that
does not exist.
You need to implement the ReadFile() method.
Which code segment should you use?

  • A. var fs = File.Open(Filename, FileMode.OpenOrCreate, FileAccess.Read, FileShare.ReadWrite);
  • B. var fs = File.Open(Filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
  • C. var fs = File.Open(Filename, FileMode.OpenOrCreate, FileAccess.Read, FileShare.Write);
  • D. var fs = File.ReadAllLines(Filename);
  • E. var fs = File.ReadAllBytes(Filename);


Answer : A

Explanation: FileMode.OpenOrCreate - Specifies that the operating system should open a file if it exists; otherwise, a new file should be created. If the file is opened with FileAccess.Read, FileIOPermissionAccess.Read permission is required. If the file access is FileAccess.Write, FileIOPermissionAccess.Write permission is required. If the file is opened with FileAccess.ReadWrite, both FileIOPermissionAccess.Read and FileIOPermissionAccess.Write permissions are required. http://msdn.microsoft.com/en-us/library/system.io.filemode.aspx FileShare.ReadWrite - Allows subsequent opening of the file for reading or writing.If this flag is not specified, any request to open the file for reading or writing (by this process or another process) will fail until the file is closed.However, even if this flag is specified, additional permissions might still be needed to access the file. http://msdn.microsoft.com/pl-pl/library/system.io.fileshare.aspx

Question 14

You are implementing a method named FloorTemperature that performs conversions
between value types and reference types. The following code segment implements the
method. (Line numbers are included for reference only.)


You need to ensure that the application does not throw exceptions on invalid conversions.
Which code segment should you insert at line 04?

  • A. int result = (int)degreesRef;
  • B. int result = (int)(double)degreesRef;
  • C. int result = degreesRef;
  • D. int result = (int)(float)degreesRef;


Answer : D

Question 15

You are developing an application that includes the following code segment. (Line numbers
are included for reference only.)


You need to ensure that the application accepts only integer input and prompts the user
each time non-integer input is entered.
Which code segment should you add at line 19?

  • A. If (!int.TryParse(sLine, out number))
  • B. If ((number = Int32.Parse(sLine)) == Single.NaN)
  • C. If ((number = int.Parse(sLine)) > Int32.MaxValue)
  • D. If (Int32.TryParse(sLine, out number))


Answer : A

Explanation: B and C will throw exception when user enters non-integer value. D is exactly the opposite what we want to achieve. Int32.TryParse - Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded. http://msdn.microsoft.com/en-us/library/f02979c7.aspx

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