Question 1

In the two-dimensional array declaration 
Dim newVar(,) As Double = {{1, 2, 3}, {4, 5, 2054}, {6, 802, 2786}} 
the comma in newVar(,) can be removed.

Accepted Answer

The comma in the declaration `newVar(,)` indicates that it is a two-dimensional array. Removing the comma would cause a syntax error or change the array's dimensionality.

Question 2

The statement
 Dim nextVar(3, 5) As Double 
declares a two-dimensional array that can store a table containing 4 columns and 6 rows of numeric data.

Accepted Answer

The statement Dim nextVar(3, 5) As Double declares a two-dimensional array that can store a table containing 4 columns and 6 rows of numeric data. However, the actual number of columns and rows depends on the way the array is later populated with data.

Question 3

Suppose a structure and an array are created with the code 
Structure Nation 
Dim name As String 
Dim continent As String 
Dim population As Double 'in millions 
Dim area As Double 'in square miles 
End Structure
 Dim nations(191) As Nation in the Declarations section of the Code editor and the array is filled with data for the 192 member nations of the UN. What will be displayed in the DataGridView control when the following code is executed? 
Dim query = From country In nations 
Where (country.continent = "Europe") And 
country.name.StartsWith("S") 
Let countryUC = country.name.ToUpper 
Let pop = (1000000 * country.population).ToString("N0") 
Let area = (country.area).ToString("N0") 
Order By countryUC Ascending
Select countryUC, pop, area

Accepted Answer

The query statement selects only three fields: countryUC, pop, and area. The condition of where (country.continent = "Europe") And country.name.StartsWith("S") restricts the output to countries in Europe whose names begin with the letter S. The Order By clause sorts the result by countryUC in ascending order, which means the countries will be displayed capitalized in alphabetical order. The formatting specifications ToString("N0") convert the values of population and area to a string with commas as thousands separators.

Question 4

Which of the following types of variables can only hold a single item of data?

Accepted Answer

Simple variables can only store a single item of data. Two-dimensional arrays, single-subscripted variables, and double-subscripted variables can all hold multiple items of data.

Question 5

Which of the following declarations creates a two-dimensional array?

Accepted Answer

The declaration "Dim newVar(2, 2) As Double" creates a two-dimensional array with 3 rows and 3 columns, as indicated by the two values in parentheses. The data type of the array is Double, meaning it can hold decimal values.

Question 6

Suppose a structure and an array are created with the code 
Structure Nation 
Dim name As String 
Dim continent As String 
Dim population As Double 'in millions 
Dim area As Double 'in square miles 
End Structure 
Dim nations(191) As Nation 
in the Declarations section of the Code editor and the array is filled with data for the 192 member nations of the UN. What will be displayed in the DataGridView control when the following code is executed? 
Dim query = From country In nations 
Where country.population > 200 
Order By country.area Descending 
Select country.name, country.continent 
dgvNations.DataSource = query.ToList
 dgvNations.CurrentCell = Nothing

Accepted Answer

The code creates a query that selects only the name and continent of countries whose population is greater than 200 million people and orders them by area in descending order. The resulting grid will display two columns (name and continent) with the corresponding data for each country, in order of their area (from largest to smallest).

Question 7

Suppose a structure is created with the code 
Structure stateUSA 
Dim capCity As String 
Dim yearFounded As Integer
 End Structure
 in the Declarations section of the Code window. In this structure, the variable capCity is known as a member.

Accepted Answer

The variable capCity is a member of the stateUSA structure because it is declared within the structure.

Question 8

Suppose a structure is created with the code 
Structure stateUSA 
Dim capCity As String 
Dim stateNum As Integer 
End Structure 
in the Declarations section of the Code window. The following statement correctly makes use of the stateNum member of this structure.

Accepted Answer

Since stateNum is a member of the stateUSA structure, it can be accessed and used in statements involving the structure.

Question 9

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

Accepted Answer

The method used to change the words in a column header of a DataGridView control is HeaderText. This property allows you to set or get the text that is displayed in the header of the column.

Question 10

How many elements are in the array declared by 
Dim myArray(3, 2) As Double

Accepted Answer

The array has 4 rows and 3 columns, so it has 12 elements.

Question 11

When a variable with a user-defined data type is passed to a procedure, the corresponding parameter in the Sub or Function statement must be declared to be of the same data type.

Accepted Answer

When passing a variable with a user-defined data type to a procedure, the parameter in the Sub or Function statement must be declared to be of the same data type as the variable being passed.

Question 12

A two-dimensional array can be declared and initialized at the same time.

Accepted Answer

A two-dimensional array can be declared and initialized using curly braces {} to enclose the values of each row, separated by commas, and enclosed in another pair of curly braces {} for the entire array. For example:

int[][] myArray = {{1,2,3}, {4,5,6}, {7,8,9}};

Question 13

Suppose a structure and an array are created with the code 
Structure Nation 
Dim name As String 
Dim continent As String 
Dim population As Double 'in millions 
Dim area As Double 'in square miles 
End Structure
 Dim nations(191) As Nation
 in the Declarations section of the Code editor and the array is filled with data for the 192 member nations of the UN. What will be displayed in the list box when the following code is executed?
 Dim query = From country In nations 
Where country.continent = "Africa" 
Order By country.population Descending 
Select country.name 
lstBox.DataSource = query.ToList 
lstBox.SelectedIndex = Nothing

Accepted Answer

The code uses LINQ to query the array of nations and filters it to only include nations in Africa. It then sorts the filtered results in descending order based on population and selects only the name of the countries. Therefore, the list box will display the names of the countries in Africa beginning with the name of the most populous country.

Question 14

Which of the following types of variables is capable of holding the information contained in a table that has four rows and four columns?

Accepted Answer

A double-subscripted variable (also known as a two-dimensional array) is capable of holding information in a table format with multiple rows and columns.

Question 15

Which of the following declarations can be used to create a three-dimensional array?

Accepted Answer

Option B declares a three-dimensional array with dimensions of 2x2x2. The other options either declare a two-dimensional array (option A) or a one-dimensional array (options C and D).

Question 16

Given the following array, what value will be assigned to num? $\text { num - myArray }(3,4)$

$\quad $$\quad $$\quad $$\quad $$\text { myArray }$
$\begin{array}{c}
\begin{array}{lll}
\
\hline 0\
1\
2\
3\
4
\end{array}
\begin{array}{|l}
0\
\hline0\
\hline5\
\hline10\
\hline15\
\hline20\
\hline
\end{array}
\begin{array}{|l|}
 1 \
\hline 1 \
\hline 6 \
\hline 11 \
\hline 16 \
\hline 21 \
\hline
\end{array}
\begin{array}{l}
2 \
\hline2\
\hline 7 \
\hline 12 \
\hline 17 \
\hline 22\
\hline
\end{array}
\begin{array}{|l|}
3 \
\hline 3 \
\hline 8 \
\hline 13 \
\hline 18 \
\hline 23 \
\hline
\end{array}
\begin{array}{l|}
4 \
\hline 4 \
\hline 9 \
\hline 14 \
\hline 19 \
\hline 24\
\hline 
\end{array}

\end{array}$

Accepted Answer

The value at position (3,4) in the array is 19.

Question 17

Arrays that are capable of holding the contents of a table with several rows and columns, are known as two-dimensional arrays or double subscripted variables.

Accepted Answer

Two-dimensional arrays are arranged in rows and columns and can hold the contents of a table with several rows and columns. They are also known as double subscripted variables because they require two indices or subscripts to access a specific element within the array.

Question 18

Suppose a structure and an array are created with the code 
Structure Nation
 Dim name As String 
Dim continent As String 
Dim population As Double 'in millions
Dim area As Double 'in square miles 
End Structure 
Dim nations(191) As Nation
 in the Declarations section of the Code editor and the array is filled with data for the 192 member nations of the UN. What will be displayed in the list box when the following code is executed?
 Dim query = From country In nations 
Order By country.area Descending 
Select country.name, country.population 
lstBox.Items.Add(query.First.name) 
lstBox.Items.Add(1000000 * query.First.population)

Accepted Answer

The query sorts the nations by their area in descending order, meaning the largest nations will come first. The code then selects the name and population of the first (i.e. largest) country in the sorted list and adds them to the list box. Therefore, the code will display the name and population of the largest country in the UN.

Question 19

If the two-dimensional array nums has three rows and six columns, then the value of nums.GetUpperBound(0) is 3 and the value of nums.GetUpperBound(1) is 6.

Accepted Answer

The value of nums.GetUpperBound(0) is 2 because it returns the highest index of the first dimension (rows), which is 0-based. The value of nums.GetUpperBound(1) is 5 because it returns the highest index of the second dimension (columns), which is also 0-based.

Question 20

A structure can contain members that are simple variables only; members cannot be arrays.

Accepted Answer

Members of a structure can be arrays in addition to simple variables.

Quiz 7: Arrays

In the two-dimensional array declaration Dim newVar(,) As Double = {{1, 2, 3}, {4, 5, 2054}, {6, 802, 2786}} the comma in newVar(,) can be removed.

The statement Dim nextVar(3, 5) As Double declares a two-dimensional array that can store a table containing 4 columns and 6 rows of numeric data.