Deck 8: Text Files

Question 1

The following statement could be used to set the Filter property of the OpenFileDialog control so that it displays files with the .txt extension.

Answer 1

False

Question 2

Opening a file for output means that

A) data may be stored onto the disk.
B) data may be read from the disk.
C) anything that appears as output on the screen is written to the disk.
D) data may be read from and stored onto the disk.

Answer 2

A

Question 3

Each line of the file UN.txt contains four pieces of information (name, continent, population in millions, area) about one of the 192 member countries of the United Nations. The first two lines of the file are
Afghanistan,Asia,28.2,251772
Albania,Europe,3.2,11100
What is the first line of the file created by the following code?
Dim query = From line In IO.File.ReadAllLines("UN.txt") Let data = line.Split(","c)
Let country = data(0) Let population = 1000000 * CDbl(data(2)) Let area = CDbl(data(3))
Let density = population / area
Select country & "," & density.ToString("N1")
IO.File.WriteAllLines("NewFile.txt", query)

A) Afganistan,28200000/251772
B) Afganistan,112.0
C) Afganistan,112.006100757829
D) country,density

Answer 3

Afganistan,112.0

Question 4

The acronym CSV stands for "Comma Separated Values".

Question 5

What method is used to copy the contents of a string array or LINQ query into a text file?

A) CreateTextFile
B) WriteAllLines
C) CopyToTextFile
D) ReadAllLines

Question 6

What property is set to False in order to remove the row header column on the left side of a DataGridView control?

A) ShowRowHeader
B) DisplayRowHeader
C) RowHeaderVisible
D) RowHeaderEnabled

Question 7

Select the example statement below that would open a text file for output.

A) Dim sw As IO.StreamWriter = IO.File.OpenText("IncomeData.txt")
B) Dim sw As IO.StreamWriter = IO.File.CreateText("IncomeData.txt")
C) Dim sr As IO.StreamReader = IO.File.OpenText("IncomeData.txt")
D) Dim sr As IO.StreamReader = IO.File.AppendText("IncomeData.txt")

Question 8

Which of the following methods is used to change the words in a column header of a DataGridView control?

A) HeaderText
B) HeaderName
C) HeaderContent
D) HeaderCaption

Question 9

The following statement causes the Open dialog box to become visible on the form. OpenFileDialog1.ShowDialog After a file has been selected and the Open button is pressed, the value of OpenFileDialog1.FileName will be the file's filespec; this will include all of the following except

A) the file's drive.
B) the file's date of creation.
C) the file's path.
D) the file's extension.

Question 10

Each record of the file UN.txt contains four pieces of information (name, continent, population in millions, area) about one of the 192 member countries of the United Nations. The first two lines of the file are
Afghanistan,Asia,28.2,251772
Albania,Europe,3.2,11100

What is the first line of the file created by the following code?
Dim query = From line In IO.File.ReadAllLines("UN.txt")
Let data = line.Split(","c)
Let country = data(0)
Let continent = data(1)
Select country & " is in " & continent
IO.File.WriteAllLines("NewFile.txt", query)

A) Afghanistan is in Asia
B) Albania is in Europe
C) country is in continent
D) The new file will be empty.

Question 11

Which of the following statements is used when you want to add data to the end of an existing text file?

A) Dim sr As IO.StreamReader = IO.File.OpenText("Data.txt")
B) Dim sr As IO.StreamReader = IO.File.AddText("Data.txt")
C) Dim sw As IO.StreamWriter = IO.File.CreateText("Data.txt")
D) Dim sw As IO.StreamReader = IO.File.AppendText("Data.txt")

Question 12

The following statement could be used to set the Filter property of the OpenFileDialog control so that it displays files with the .txt extension.

Question 13

A statement of the form IO.File.WriteAllLines("fileName.txt", numArray) copies the contents of the numeric array numArray into a text file.

Question 14

Opening a file for input means that

A) data may be stored onto the disk.
B) data may be read from the disk.
C) anything that appears as output on the screen is written to the disk.
D) data may be read from and stored onto the disk.

Question 15

When an existing file is opened for Output

A) new data are added at the end of the existing file.
B) the file is erased completely and new data are added at the beginning of the file.
C) Visual Basic generates an error message and stops program execution.
D) data may be read from it.

Question 16

In order to use the OpenFileDialog control, the programmer must first change its Name property to something other than the default OpenFileDialog1.

Question 17

When a file is opened for Append,

A) data may be read starting at the beginning of the file.
B) data written to the file replaces the data already there.
C) data written to the file are inserted at the beginning of the file.
D) data written to the file are added at the end of the file.

Question 18

Assume the file Alphabet.txt contains 26 records, the lowercase letters of the alphabet in ascending order. What happens when the following code is executed?
Dim letter As String
Dim sr As IO.StreamReader = IO.File.OpenText("Alphabet.txt")
Do While Not sr.EndOfStream
Dim sw As IO.StreamWriter = IO.File.CreateText(letter.ToUpper & ".txt") letter = sr.ReadLine
sw.WriteLine(letter.ToUpper & ".txt")
sw.Close
Loop
sr.Close

A) A "too many files open" error is produced.
B) Twenty-six files are created and named with one of the uppercase letters of the alphabet and each containing only its own file name.
C) A file called z is created containing all of the letters of the alphabet in lowercase.
D) An "invalid file name" error is produced.

Question 19

When you place the OpenFileDialog control on a form, it will not be visible on the form.

Question 20

Each line of the file UN.txt contains four pieces of information (name, continent, population in millions, area) about one of the 192 member countries of the United Nations. The first two lines of the file are
Afghanistan,Asia,28.2,251772
Albania,Europe,3.2,11100
What is the first line of the file created by the following code? Dim query = From line In IO.File.ReadAllLines("UN.txt") Let data = line.Split(","c)
Let country = data(0)
Let population = 1000000 * CDbl(data(2))
Select country & "," & population
IO.File.WriteAllLines("NewFile.txt", query)

A) Afganistan,28.2
B) Afganistan,28,200,000
C) Afganistan,28200000
D) country,population

Question 21

The following statements are valid.
Dim filespec As String
filespec = InputBox ("Enter name of file to process:")
Dim sr As IO.StreamReader = IO.File.OpenText (filespec)

Question 22

In the following statement, sw is the name of a variable.
Dim sw As IO.StreamWriter =
$\quad$$\quad$$\quad$$\quad$$\quad$ IO.File.CreateText ("C:\TEXT FILES\INCOME Data.txt")

Question 23

If a text file is opened for input, then this allows

A) data to be placed into the file by the Visual Basic application.
B) data that is in the file to be used in the Visual Basic application.
C) data to be appended to the end of the file by the Visual Basic application.
D) data to be deleted from the file.

Question 24

To get rid of an existing closed file, execute a statement of the form IO.File.Delete(filespec).

Question 25

When a text file is created in Visual Basic using a StreamWriter, the extension .txt is automatically added to the file name if no other extension is specified.

Question 26

Consider the following code. The Catch block of code will not be executed if the user enters which of the following when prompted?
Private Sub btnCalc_Click(...) Handles btnCalc.Click
Dim newNum, finalNum As Integer
Dim message, message1 As String
Try
newNum = CInt(InputBox("How old are you?"))
Catch
message = "That answer is not an Integer value."
MessageBox.Show(message)
newNum = 0
Finally finalNum = newNum + 1
message1 = "Your age next year will be " & finalNum & "."
MessageBox.Show(message1)
End Try
End Sub

A) one
B) 0
C) 3000000000
D) *

Question 27

Which of the following statements will result in an IndexOutOfRangeException if placed after the following line of code?
Dim arr(2) As Integer

A) arr(3) = 2
B) arr(2) = 2
C) arr(1) = 2
D) arr(0) = 2

Question 28

Which one of the following is NOT an example of a bug?

A) viruses
B) accessing the wrong property value
C) using an incorrect formula
D) typos

Question 29

The catch block:
Catch exc As IO.IOException
handles which of the following exceptions?

A) any exception that hasn't been handled by the Try block
B) an exception generated by deleting or renaming an open file
C) an exception generated by attempting to access a file that is missing
D) an exception generated by attempting to access a file within a folder that is missing

Question 30

The value of sr.EndOfStream is True when the end of file accessed by the StreamReader is reached.

Question 31

When an exception is generated by a Visual Basic application, the default exception handler will

A) restart the program.
B) terminate the program.
C) continue to execute the program.
D) display a dialog box that asks the user if they wish to restart the computer.

Question 32

The line of code
sw.Close
when used with the line
sw = IO.File.CreateText(fileName)
completes which of the following tasks?

A) it closes the current application
B) it closes the current form
C) it closes the currently opened window of the application
D) it closes the file referred to by the variable name sw

Question 33

An individual item of a text file cannot be changed or deleted directly.

Question 34

Which of the following exceptions will be generated by trying to access a disk drive that doesn't contain a disk?

A) NullReferenceException
B) IndexOutOfRangeException
C) IO.DirectoryNotFoundException
D) OverflowException

Question 35

If an existing text file is opened for output, the computer will append any new data to the end of this existing file.

Question 36

Which exception will the following code generate?
Dim num1 As Integer, num2 As Integer = 1000000
num1 = num2 * num2

A) NullReferenceException
B) ArgumentOutOfRangeException
C) OverflowException
D) InvalidCastException

Question 37

Text files are updated by opening them for Input and then entering the new data.

Question 38

If the value of IO.File.Exists(filespec) is True, then the specified file exists.

Question 39

The code in a Try block refers to a file and the first catch block is written as follows: Catch exc As IO.IOException
The second catch block is written with the following clause:
Catch

What type of exception will this second Catch block handle?

A) any exception that hasn't already been handled
B) an exception generated by deleting or renaming an open file
C) this block isn't designed to catch any exceptions
D) this block will catch all cases where the file specified by fileName does exist

Question 40

Which exception will the following code generate?
Dim str As String
str = "Visual Basic".Substring(14,2)

A) NullReferenceException
B) ArgumentOutOfRangeException
C) OverflowException
D) InvalidCastException

Question 41

Element names are case sensitive.

Question 42

Comment statements in XML begin with

Question 43

Before a text file can be opened for input, it must already exist on a disk.

Question 44

When using Try-Catch-Finally blocks, the programmer is limited to three Catch blocks of code.

Question 45

A Catch block of code that is initiated by the keyword Catch and doesn't contain any additional terms will execute regardless of whether an exception occurred.

Question 46

A text file cannot be open both for input and for output at the same time.

Question 47

If any record in a text file is to be changed, the entire file must be rewritten.

Question 48

In a Try-Catch-Finally block, the code in the first listed Catch block is executed if an exception is thrown in the Try block.

Question 49

If an attempt is made to access a file within a missing folder using the OpenText method, the IO.DirectoryNotFoundException will be thrown.

Question 50

The XML standard was recommended by the World Wide Web Consortium.

Question 51

Placing the statement Imports System.IO near the top of the Code Editor (before the Class frmName statement) simplifies file handling by eliminating the need to use the words StreamReader, StreamWriter, and File in your code.

Question 52

Which of the following terms is NOT used to refer to a part of an XML document?

A) content
B) element
C) start tag
D) title

Question 53

In the line of code sw = IO.File.CreateText(fileName) sw is a variable that holds the value of a filespec for an existing text file.

Question 54

Each element of an XML document must contain both a start tag and an end tag.

Question 55

In a Try-Catch-Finally block, the Catch clauses are considered one at a time, in the order in which they appear in the code, until the proper exception is located.

Question 56

Before a text file can be opened for append, it must already exist on a disk.

Question 57

In a Try-Catch-Finally block, if there are multiple Catch blocks, the code in the last listed Catch block is always executed.

Question 58

XML stands for

A) extreme markup language
B) excessive markup language
C) extraordinary markup language
D) extensible markup language

Question 59

End tags always begin with a less than symbol followed by a forward slash.

Question 60

In a Try-Catch-Finally block, the code in the Finally block is always executed, regardless of whether an exception was thrown.

Question 61

XML files must be loaded into XElement objects before being accessed with LINQ.

Question 62

Elements in an XML document can contain other elements.

Question 63

An XML file can contain several root elements.

Question 64

The characters < and & cannot appear in the content of an element of an XML file.

Question 65

Which of the following terms is NOT used to refer to elements in an XML document?

A) child
B) basis
C) sibling
D) parent