Question 1

A List object has a(n) ____________ that holds the number of items stored in the List.
A) Count property
B) Total property
C) Length property
D) Size property

Accepted Answer

The Count property is used in C# to represent the number of elements in a List. It is a built-in property of the List class and returns an integer value representing the number of elements in the List.

Question 2

If you want to take out all items from a List object, call the ____________ method.
A) Clear
B) Reset
C) ClearAll
D) ReDim

Accepted Answer

The Clear method removes all items from a List object. Therefore, A is the best choice. The other options, Reset, ClearAll, and ReDim, either do not exist or are not applicable to removing items from a List object.

Question 3

You can use the ____________ to take out an item at a specific index in a List.
A) Delete method
B) RemoveAt method
C) DeleteAt method
D) EraseAt method

Accepted Answer

The RemoveAt method is specifically designed to remove an item at a specific index in a List. The Delete, DeleteAt, and EraseAt methods do not exist in the List class and would result in errors.

Question 4

You can call the ____________ method to insert an item at a specific index position in a List object.
A) Put
B) Add
C) Insert
D) Place

Accepted Answer

The Insert method is specifically designed to insert an item at a specific index position in a List object, whereas the Put and Place methods do not exist in the List class. The Add method can add an item to the end of the list, but it cannot insert an item at a specific index position.

Question 5

Memory allocated for a reference type variable is the actual location that will hold any value assigned to the variable.

Accepted Answer

Memory allocated for a reference type variable actually holds a reference (or address) to the location in memory where the actual value is stored, not the value itself.

Question 6

Look at the following code sample: int[,] values = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 } };
What is the value stored in values[1, 2]?
A) 2
B) 3
C) 6
D) 7

Accepted Answer

values[1,2] refers to the element in the second row and third column of the array. Therefore, the value stored in values[1,2] is 7.

Question 7

Reference variables can only reference objects.

Accepted Answer

This statement is true. Reference variables are used to refer to objects in memory. They cannot refer to other types of data such as primitive types or null values.

Question 8

Which one of the following statements correctly creates a List object named friendsList that holds strings? A) string friendsList = new List; B) friendsList(string); C) List friendsList = new List; D) List friendsList = new List();

Accepted Answer

Option D correctly creates a List object named friendsList that holds strings. It uses the List<> generic type with a parameter of string and initializes it using the empty constructor (). Option A creates a string variable with the name friendsList instead of a List object. Option B is syntactically incorrect, and option C is similar to option D but missing the initialization using ().

Question 9

A(n) ____________ is similar to an array, but it can expand at runtime.
A) List object
B) sequential object
C) Random object
D) jagged array

Accepted Answer

A List object is similar to an array, but it can expand at runtime. It can dynamically grow or shrink as needed, making it a more flexible option than a traditional array.

Question 10

If you know the value of the item you want to take out from a List object, but you do not know the item's index, you can use the ____________.
A) - (minus) operator
B) Erase method
C) Remove method
D) Delete method

Accepted Answer

The Remove method is used to remove an item from a List object based on its value. It takes the item's value as an argument and searches the list for the first occurrence of that value, then removes it from the list. This method does not require you to know the index of the item, making it a good choice for this scenario.

Question 11

A(n) ____________ is similar to a two-dimensional array, but the rows can have a different number of columns.
A) offset array
B) skewed array
C) jagged array
D) differential array

Accepted Answer

A jagged array is a type of array in which the rows can have a different number of columns. It is also known as a ragged array, uneven array, or sparse array. It is useful when the data being stored has a variable number of elements in each row. The other options, offset array, skewed array, and differential array, are not types of arrays commonly used in programming.

Question 12

Data types in C# − and the underlying .NET Framework − fall into two categories: value types and reference types.

Accepted Answer

This statement is true. C# and .NET Framework have two categories of data types: value types and reference types.

Question 13

List objects, like arrays, are always passed to methods ____________.
A) by value
B) in memory
C) by reference
D) globally

Accepted Answer

Lists, like most objects in Python, are passed by reference. This means that any changes made to the list inside the method will affect the original list that was passed in, rather than creating a new copy.

Question 14

Look at the following code sample: const int ROWS = 2;
Const int COLS = 2;
Int[,] grid = new int[ROWS, COLS];
What is the total number of elements in the grid array?
A) 2
B) 4
C) 8
D) 16

Accepted Answer

The total number of elements in the grid array is equal to the product of ROWS and COLS, which is 2x2=4. Therefore, the correct choice is B.

Question 15

You can store a variety of data types in an array.

Accepted Answer

In most programming languages, arrays are designed to store elements of the same data type, although some languages or data structures allow mixed types.

Question 16

Creating a reference type object typically requires the following two steps, which can optionally be coded in a single program statement:
1. Declare a reference variable.
2. Create an object and associate it with the reference variable.

Accepted Answer

This is correct, creating a reference type object involves declaring a reference variable and then creating an object and associating it with the reference variable. These two steps can be combined into a single program statement.

Question 17

Look at the following code sample: const int ROWS = 8;
Const int COLS = 2;
Int[,] table = new int[ROWS, COLS];
Which one of the following statements stores the value 25 in the element located at the first row and second column of the table array?
A) table[1, 2] = 25;
B) table[0, 1] = 25;
C) table[2, 1] = 25;
D) table[1, 0] = 25;

Accepted Answer

Since the array is zero-indexed, the first row is indexed as 0 and the second column is indexed as 1. Therefore, to store the value 25 in the element located at the first row and second column of the table array, we need to use the index [0, 1]. The correct statement is table[0, 1] = 25.

Question 18

Because variables hold only single values, they can be cumbersome in programs that process lists of data.

Accepted Answer

Variables can hold only single values, making it difficult to process a list of data. Therefore, more complex data structures like arrays or lists are used in programs that need to process extensive datasets.

Question 19

Traditional two-dimensional arrays, where each row has the same number of columns, are sometime referred to as ____________.
A) square arrays
B) rectangular arrays
C) box arrays
D) 2D arrays

Accepted Answer

Traditional two-dimensional arrays are often referred to as rectangular arrays because each row has the same number of columns, creating a rectangular shape. While square arrays are also two-dimensional, they have an equal number of rows and columns, creating a square shape. Box arrays and 2D arrays are not commonly used terms for traditional two-dimensional arrays.

Question 20

To add items to an existing List object, use the ____________.
A) += operator
B) & operator
C) Insert property
D) Add method

Accepted Answer

The Add method is used to add items to an existing List object. The += operator is not supported for List objects, and the & operator does not apply here. The Insert property is not a valid property for List objects.

Quiz 7: Arrays and Lists

A List object has a(n) ____________ that holds the number of items stored in the List.

If you want to take out all items from a List object, call the ____________ method.

You can use the ____________ to take out an item at a specific index in a List.

You can call the ____________ method to insert an item at a specific index position in a List object.

Memory allocated for a reference type variable is the actual location that will hold any value assigned to the variable.

Look at the following code sample: int[,] values = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 } }; What is the value stored in values[1, 2]?

Reference variables can only reference objects.

Which one of the following statements correctly creates a List object named friendsList that holds strings?

A(n) ____________ is similar to an array, but it can expand at runtime.

If you know the value of the item you want to take out from a List object, but you do not know the item's index, you can use the ____________.

A(n) ____________ is similar to a two-dimensional array, but the rows can have a different number of columns.

Data types in C# − and the underlying .NET Framework − fall into two categories: value types and reference types.

List objects, like arrays, are always passed to methods ____________.

Look at the following code sample: const int ROWS = 2; Const int COLS = 2; Int[,] grid = new int[ROWS, COLS]; What is the total number of elements in the grid array?

You can store a variety of data types in an array.

Creating a reference type object typically requires the following two steps, which can optionally be coded in a single program statement: 1. Declare a reference variable. 2. Create an object and associate it with the reference variable.

Look at the following code sample: const int ROWS = 8; Const int COLS = 2; Int[,] table = new int[ROWS, COLS]; Which one of the following statements stores the value 25 in the element located at the first row and second column of the table array?

Because variables hold only single values, they can be cumbersome in programs that process lists of data.

Traditional two-dimensional arrays, where each row has the same number of columns, are sometime referred to as ____________.

To add items to an existing List object, use the ____________.