A Basic C# Skills Test Questions!

1. Will the finally block get executed if an exception has not occurred?

Yes

No

The finally block will always get executed, regardless of whether an exception has occurred or not. This block is used to perform any necessary cleanup operations, such as closing files or releasing resources, and it ensures that these operations are executed even if an exception is thrown. Therefore, even if no exception occurs, the finally block will still be executed.

Explanation

The finally block will always get executed, regardless of whether an exception has occurred or not. This block is used to perform any necessary cleanup operations, such as closing files or releasing resources, and it ensures that these operations are executed even if an exception is thrown. Therefore, even if no exception occurs, the finally block will still be executed.

2. The C# keyword "int" maps to which .NET type?

System.Int16

System.Int32

System.Int64

System.Int128

The C# keyword "int" maps to the .NET type System.Int32. This is because "int" in C# represents a 32-bit signed integer, and System.Int32 is the corresponding .NET type for this data type.

Explanation

The C# keyword "int" maps to the .NET type System.Int32. This is because "int" in C# represents a 32-bit signed integer, and System.Int32 is the corresponding .NET type for this data type.

3. Does .NET support the ability to inherit multiple interfaces?

Yes

No

.NET does support the ability to inherit multiple interfaces. This feature is known as multiple interface inheritance and allows a class to inherit from multiple interfaces, enabling it to implement the methods and properties defined in each interface. This feature provides flexibility and allows for better code organization and reusability.

Explanation

.NET does support the ability to inherit multiple interfaces. This feature is known as multiple interface inheritance and allows a class to inherit from multiple interfaces, enabling it to implement the methods and properties defined in each interface. This feature provides flexibility and allows for better code organization and reusability.

4. Can you change the value of a variable while debugging a C# application?

Yes

No

Yes, you can change the value of a variable while debugging a C# application. Debugging allows you to pause the execution of the program at a specific point and inspect the values of variables. You can modify the value of a variable during debugging to test different scenarios and analyze the behavior of the program. This can be done by simply editing the value in the debugger's interface.

Explanation

Yes, you can change the value of a variable while debugging a C# application. Debugging allows you to pause the execution of the program at a specific point and inspect the values of variables. You can modify the value of a variable during debugging to test different scenarios and analyze the behavior of the program. This can be done by simply editing the value in the debugger's interface.

5. Does C# support multiple inheritances?

Yes

No

C# does not support multiple inheritances. Multiple inheritances refer to the ability of a class to inherit from multiple base classes. In C#, a class can only inherit from a single base class. This is done to avoid the ambiguity and complexity that can arise from multiple inheritance, as it can lead to conflicts when two or more base classes have methods or properties with the same name. To achieve similar functionality, C# supports interfaces, which allow a class to implement multiple interfaces and inherit their methods and properties.

Explanation

C# does not support multiple inheritances. Multiple inheritances refer to the ability of a class to inherit from multiple base classes. In C#, a class can only inherit from a single base class. This is done to avoid the ambiguity and complexity that can arise from multiple inheritance, as it can lead to conflicts when two or more base classes have methods or properties with the same name. To achieve similar functionality, C# supports interfaces, which allow a class to implement multiple interfaces and inherit their methods and properties.

6. Which common design pattern is shown below? public class A { private A instance; private A() { } public static A Instance { get { if(instance == null) instance = new A(); return instance; } } }

Factory

Abstract Factory

Singleton

Builder

The given code snippet demonstrates the Singleton design pattern. In this pattern, a class has a private constructor and a static method that returns the same instance of the class every time it is called. The private variable "instance" is used to store the single instance of the class, and the static method "Instance" checks if the instance is null and creates a new instance if it is. This ensures that only one instance of the class is created and accessed throughout the application.

Explanation

The given code snippet demonstrates the Singleton design pattern. In this pattern, a class has a private constructor and a static method that returns the same instance of the class every time it is called. The private variable "instance" is used to store the single instance of the class, and the static method "Instance" checks if the instance is null and creates a new instance if it is. This ensures that only one instance of the class is created and accessed throughout the application.

7. Which .NET collection class allows elements to be accessed using a unique key?

ListDictionary

Stack

Hashtable

ArrayList

StringCollection

The Hashtable class in .NET allows elements to be accessed using a unique key. It is a collection class that stores key-value pairs, where each key is unique and used to access its corresponding value. This class provides fast lookup and retrieval of elements based on their keys, making it suitable for scenarios where quick access to specific elements is required. Unlike other collection classes like ArrayList or Stack, Hashtable provides efficient key-based access to elements.

Explanation

The Hashtable class in .NET allows elements to be accessed using a unique key. It is a collection class that stores key-value pairs, where each key is unique and used to access its corresponding value. This class provides fast lookup and retrieval of elements based on their keys, making it suitable for scenarios where quick access to specific elements is required. Unlike other collection classes like ArrayList or Stack, Hashtable provides efficient key-based access to elements.

8. What is the top .NET class that everything is derived from?

Object

System.Net

System.Object

System

System.Root

The top .NET class that everything is derived from is System.Object. In .NET, all classes are derived from the Object class, which provides the most basic functionality that all objects share, such as methods for cloning, comparing, and converting objects. This class serves as the root of the class hierarchy in .NET and is implicitly inherited by all other classes.

Explanation

The top .NET class that everything is derived from is System.Object. In .NET, all classes are derived from the Object class, which provides the most basic functionality that all objects share, such as methods for cloning, comparing, and converting objects. This class serves as the root of the class hierarchy in .NET and is implicitly inherited by all other classes.

9. Multiple catch blocks can be executed for a single try statement.

True

False

In most programming languages like Java and C#, only one catch block is executed for a single try statement. When an exception occurs, the runtime checks each catch block in order and executes the first one that matches the type of the exception. Once a matching catch block is executed, no further catch blocks are executed.

Explanation

In most programming languages like Java and C#, only one catch block is executed for a single try statement. When an exception occurs, the runtime checks each catch block in order and executes the first one that matches the type of the exception. Once a matching catch block is executed, no further catch blocks are executed.

10. Which of these statements correctly declares a two-dimensional integer array in C#?

Int[,] myArray;

Int[][] myArray;

Int[2] myArray

System.Array[2] myArray;

System.Array[,] myArray;

The correct answer is int[,] myArray; because it declares a two-dimensional integer array in C#. The int[,] syntax specifies that the array will have two dimensions, and myArray is the name given to the array variable.

Explanation

The correct answer is int[,] myArray; because it declares a two-dimensional integer array in C#. The int[,] syntax specifies that the array will have two dimensions, and myArray is the name given to the array variable.

11. In Object Oriented Programming, which answers best describes encapsulation?

The conversion of one type of object to another.

The runtime resolution of method calls.

The exposition of data.

The separation of interface and implementation.

Encapsulation in object-oriented programming refers to the practice of hiding the internal details of an object and exposing only the necessary information through a well-defined interface. This allows for better control over the object's behavior and prevents direct access to its internal data. The separation of interface and implementation is the best description of encapsulation as it emphasizes the importance of hiding the implementation details while providing a clear and defined interface for interacting with the object.

Explanation

Encapsulation in object-oriented programming refers to the practice of hiding the internal details of an object and exposing only the necessary information through a well-defined interface. This allows for better control over the object's behavior and prevents direct access to its internal data. The separation of interface and implementation is the best description of encapsulation as it emphasizes the importance of hiding the implementation details while providing a clear and defined interface for interacting with the object.

12. If a method is marked as protected internal, who can access it?

Classes that are both in the same assembly and derived from the declaring class.

Only methods that are in the same class as the method in question.

Internal methods can only be called using reflection.

Classes within the same assembly, and classes derived from the declaring class.

A method marked as protected internal can be accessed by classes within the same assembly and classes derived from the declaring class. This means that any class within the same assembly can access the method, regardless of whether it is derived from the declaring class or not. Additionally, any class that is derived from the declaring class, regardless of whether it is in the same assembly or not, can also access the method.

Explanation

A method marked as protected internal can be accessed by classes within the same assembly and classes derived from the declaring class. This means that any class within the same assembly can access the method, regardless of whether it is derived from the declaring class or not. Additionally, any class that is derived from the declaring class, regardless of whether it is in the same assembly or not, can also access the method.

13. Which of the following operations can you NOT perform on an ADO.NET DataSet?

A DataSet can be synchronized with the database.

A DataSet can be synchronized with a RecordSet.

A DataSet can be converted to XML.

You can infer the schema from a DataSet.

ADO.NET DataSet cannot be synchronized with a RecordSet. A RecordSet is a data structure in ADO (ActiveX Data Objects) technology, which is used to represent a set of records from a database table. ADO.NET DataSet, on the other hand, is a disconnected, in-memory representation of data that can be retrieved from a database using ADO.NET technology. While a DataSet can be synchronized with a database and can be converted to XML, it cannot be synchronized with a RecordSet as RecordSet is specific to ADO technology.

Explanation

ADO.NET DataSet cannot be synchronized with a RecordSet. A RecordSet is a data structure in ADO (ActiveX Data Objects) technology, which is used to represent a set of records from a database table. ADO.NET DataSet, on the other hand, is a disconnected, in-memory representation of data that can be retrieved from a database using ADO.NET technology. While a DataSet can be synchronized with a database and can be converted to XML, it cannot be synchronized with a RecordSet as RecordSet is specific to ADO technology.

14. Which compiler switch creates an xml file from the xml comments in the files in an assembly?

/text

/doc

/xml

/help

/xmlhelp

The /doc compiler switch in C# is used to create an XML file from the XML comments in the source code files of an assembly. This switch generates an XML documentation file that contains the comments formatted in XML, which can then be used for creating external documentation or for use with IntelliSense in Visual Studio. Other options like /text, /xml, /help, and /xmlhelp do not serve this purpose.

Explanation

The /doc compiler switch in C# is used to create an XML file from the XML comments in the source code files of an assembly. This switch generates an XML documentation file that contains the comments formatted in XML, which can then be used for creating external documentation or for use with IntelliSense in Visual Studio. Other options like /text, /xml, /help, and /xmlhelp do not serve this purpose.

15. What will be the output of the following C# code snippet? int[] numbers = { 1, 2, 3, 4, 5 }; int result = 0; for (int i = 0; i < numbers.Length; i++) { result += (i % 2 == 0) ? numbers[i] * 2 : numbers[i] / 2; } Console.WriteLine(result);

18

19

20

21

The code loops through the numbers array, doubling the value at even indices and halving the value at odd indices. The calculations are as follows: (1*2) + (2/2) + (3*2) + (4/2) + (5*2) = 2 + 1 + 6 + 2 + 10 = 21. Therefore, the correct output is 21. This process demonstrates how conditional logic within a loop can alter the operations applied to array elements in C#.

Explanation

The code loops through the numbers array, doubling the value at even indices and halving the value at odd indices. The calculations are as follows: (1*2) + (2/2) + (3*2) + (4/2) + (5*2) = 2 + 1 + 6 + 2 + 10 = 21. Therefore, the correct output is 21. This process demonstrates how conditional logic within a loop can alter the operations applied to array elements in C#.

16. Which of these words are part of the "ACID" rule of thumb for database transactions? Select all that apply.

Isolated

Connected

Durable

Atomic

Integrity

The word "Isolated" is part of the "ACID" rule of thumb for database transactions. In the context of databases, ACID stands for Atomicity, Consistency, Isolation, and Durability. Isolation refers to the property that ensures each transaction is executed independently and doesn't interfere with other transactions. It guarantees that concurrent transactions do not affect each other's results. Therefore, "Isolated, Durable and Atomic" are correct answers as they aligns with the ACID principle.

Explanation

The word "Isolated" is part of the "ACID" rule of thumb for database transactions. In the context of databases, ACID stands for Atomicity, Consistency, Isolation, and Durability. Isolation refers to the property that ensures each transaction is executed independently and doesn't interfere with other transactions. It guarantees that concurrent transactions do not affect each other's results. Therefore, "Isolated, Durable and Atomic" are correct answers as they aligns with the ACID principle.

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