30 Questions that Define the Core of C#/.NET Development

You may raise many questions when it comes to .NET Core development since it is a bit hard to understand especially if you are a beginner. That’s why these 30 FAQs will be your best guide to learning.

1. what advantages does the .NET framework offer?

.NET is a software development platform introduced by Microsoft in 2002. Initially, it was designed for Windows applications, but with the release of .NET Core in 2016, it gained cross-platform support. The release of .NET 5 (2020) and .NET 6 (2021) made it easier to build applications across Windows, Linux, and macOS systems.

Today, .NET is a free, cross-platform, open-source developer platform for building many kinds of applications. It can run programs written in multiple languages, with C# being the most popular. It relies on a high-performance runtime that is used in production by many high-scale apps.

Cross-Platform Development: .NET Core (now .NET 5/6/7) allows building applications that run on multiple platforms such as Windows, Linux, and macOS.

Language Interoperability: It supports multiple programming languages (like C#, VB.NET, F#) and allows them to work together seamlessly in the same application.

Rich Library Support: The framework provides a large collection of pre-built libraries and tools that make development faster and more efficient.

Improved Performance: With features like Just-In-Time (JIT) compilation and garbage collection, .NET applications run efficiently with optimized performance.

(The garbage collector is basically responsible for automatic memory management. It periodically scans heap memory, so that it can automatically reclaim unused heap memory.)

2. Describe variables of value type and reference type. Provide examples for each type.

Definition: Value types directly hold their data in the memory where the variable is stored. Each variable of a value type has its own copy of the data, and operations on one variable do not affect another.

Memory Allocation: Value types are usually stored on the stack.

Examples of Value Types:

• Primitive data types like int, float, double, bool, and char.
• User-defined types such as struct and enum.

Definition: Reference types store references (or memory addresses) to the actual data rather than the data itself. When we assign a reference type variable to another, both variables point to the same location in memory, so changes made to one will reflect in the other.

Memory Allocation: Reference types are usually stored on the heap, but the reference itself is stored on the stack.

Examples of Reference Types:

• class, interface, string, array, delegate, and object.

3. Describe the use of breakpoints in debugging.

A breakpoint is a tool used in debugging that allows a developer to pause the execution of a program at a specific line of code. This pause helps in examining the program’s state at that point, including variables, memory usage, and control flow. Here’s how breakpoints are useful in debugging:

1. Isolating Bugs: Breakpoints help isolate the location of bugs by stopping the program at a specific place, allowing developers to check if the code behaves as expected.
2. Step-by-Step Execution: Once a breakpoint is hit, we can go through the code line by line to observe the program’s behavior in a controlled manner.
3. Variable Inspection: At a breakpoint, we can inspect the values of variables, expressions, and objects to verify if they hold the expected data.
4. Conditional Breakpoints: These are breakpoints that trigger only when a specific condition is met, making them useful for investigating problems that occur only under certain circumstances.
5. Monitoring Control Flow: Breakpoints allow us to see how the program’s flow is proceeding, especially in loops or conditional statements, ensuring the correct branches of code are being executed.

4. Explain the difference between the Auto window and the Watch window in C#

n C#, both the Auto Window and the Watch Window are tools used in Visual Studio to help us debug our code by inspecting variables and expressions.

The Auto Window automatically shows variables and expressions that are relevant to the current line of code we are debugging.

The Watch Window lets us manually choose which variables and expressions to monitor.

We manually choose what to track. It’s like setting up a custom list of variables or expressions we want to keep an eye on throughout our debugging session

5. What is an implicitly typed variable in C#?

An implicitly typed variable is declared using the var keyword without explicitly specifying its data type. The compiler infers the type of the variable at compile time based on the assigned value.

var myNumber = 10;  // The compiler infers the type as int

6. What is the difference between float and double data types in C#, and how do you declare them?

float:

• Size: 32 bits(4 bytes).
• Precision: 6-7 decimal digits.
• Declaration: Need to append an “F” or “f” to the value when assigning to a float

double:

• Size: 64 bits(8 bytes).
• Precision: 15-16 decimal digits.
• Declaration: Adding “D” or “d” to the value is optional since C# treats decimal literals as double by default.

7. What is type casting in C#, and how do you perform explicit and implicit type casting? Provide examples.

Type casting in C# refers to converting a variable from one data type to another. There are two types of casting: implicit casting and explicit casting.

1. Implicit Casting (automatically done by C#):
   • Happens when we convert a smaller data type to a larger one without data loss.
   • No special syntax is required.

2. Explicit Casting (manually done by the programmer):

• Required when converting from a larger type to a smaller type, or between incompatible types.
• This may result in data loss, so it needs to be done explicitly using parentheses.

8. What is the conditional (ternary) operator in C#, and how does it work? Provide an example.

It is a ternary operator which is a shorthand version of the if-else statement. It has three operands hence the name ternary. It will return one of two values depending on the value of a Boolean expression.

condition ? first_expression : second_expression;

condition: It must be evaluated as true or false.
If the condition is true
first_expression is evaluated and becomes the result.
If the condition is false,
second_expression is evaluated and becomes the result.

9. How does the switch statement in C#

The switch statement is an alternative to long if-else-if ladders. The expression is checked for different cases and the one match is executed. break statement is used to move out of the switch. If the break is not used, the control will flow to all cases below it, until the switch comes to an end. There is a default case (optional) at the end of the switch, if none of the case matches then the default case is executed.

10. What is the difference between a while loop and a do-while loop in C#?

A while loop executes the loop body if the condition is true, while a do-while loop executes the loop body at least once before checking the condition.

11. What are the differences between a for loop and a foreach loop in C#, and when would you use each?

In C#, both for and foreach loops are used for iteration, but they have distinct characteristics and use cases

for Loop:

• Usage: Ideal for scenarios where we need to control the iteration with an index or a counter

Characteristics:

• Allows more control over the loop variable.
• Can be used to iterate with complex conditions and increments.

foreach Loop:

• Usage: Best suited for iterating over collections or arrays where we do not need to modify the collection and are only interested in accessing each element

Characteristics:

• Provides a more concise and readable way to iterate through collections.

12. How do the continue and break statements work in loops in C#, and what are their effects? Provide examples to illustrate their usage.

The break statement is used to terminate the loop or statement in which it
present.

If the break statement is present in the nested loop, then it terminates only those loops that contain break statement

C# programming language-යෙහි break statement එක භාවිතා කරන්නේ loops (උදාහරණයක් ලෙස for, while, do-while) හෝ switch statement එකක අවශ්‍ය උන විටකදී execution එක නතර කරන්න.

මෙහිදී, i == 5 වීමෙන් loop එකෙන් පිටවෙනවා .break statement එක switch statement එකකද case එකක් satisfy වීමෙන් පසු execution එක නතර කිරීමට භාවිතා කරනවා.

The Continue statement is used to skip the current iteration of the loop and proceed to the next iteration, effectively bypassing the remaining code within the loop body for that iteration.

13. What is the goto statement in C#, and how is it used?

In C#, the goto statement allows us to jump to a specific label in the code. A label is a marker in the code that is identified by a name followed by a colon.

14. How does exception handling work in C#, and what is the purpose of using try, catch, and finally blocks?

C# exception handling is basically built around four keywords:
throw, try, catch, and finally.

Exception handling is a mechanism in which errors or exceptions that occur during the program execution are caught and handled gracefully. It involves using try-catch blocks to catch exceptions and handle them appropriately.

It helps ensure that our program can handle unexpected situations gracefully without crashing.

we can handle multiple exceptions in C# using a try-catch block with multiple catch clauses.

The finally block is guaranteed to execute whether an exception is thrown or not. This makes it ideal for releasing resources or performing cleanup tasks that must occur even if an error happens.

The finally block in exception handling is used to ensure that certain code is always executed, regardless of whether an exception was thrown or not.

The throw statement allows us to create a custom error.

The throw statement is used together with an exception class. There are many exception classes available in C#: ArithmeticException, FileNotFoundException, IndexOutOfRangeException, TimeOutException, etc:

15. How do you declare and initialize an array in C#?

An array is a collection of elements of the same data type. The elements are stored at contiguous memory locations. Once an array is created in C#, its size is fixed and cannot be changed.

In C#, we can declare and initialize an array in several ways:

Declaration and Initialization in One Line:

Declaration and Initialization Separately:

Declaration with Size Only:

16. What is a jagged array in C#?

A jagged array is an array of arrays(array of arrays), where each element of the main array is itself an array. Jagged arrays can have different lengths for each sub-array.

A jagged array is an array whose elements are arrays, possibly of different sizes.

17. How can you use System.Linq to perform operations on arrays in C#?

System.Linq provides a set of powerful methods to perform various operations on arrays, including filtering, sorting, projecting, and aggregating data

Example for Sum

The Sum method calculates the total of all elements in an array

18. What is a recursive method call in C#, and how is it used? Provide an example

A recursive method call in C# is when a method calls itself in order to solve a problem.

19. What is an enum in C#, and how is it used?

In C#, an enum (short for “enumeration”) is a value type that allows us to define a set of named constants. These constants are associated with numeric integer values by default, starting from 0, but when you can also assign specific values if needed.

Some of the key benefits of using enumerations:

• Improved Code Readability
• Enhanced Maintainability
• Type Safety

Usage of enumeration

20. What are the key features of structures in C#?

Structures in C# have the following key features:

• They can contain methods, fields, indexers, properties, operator methods, and events.
• structures cannot have a default constructor. It can contain a parameterized constructor, static constructor
• Unlike classes, structures cannot inherit from other structures or classes
• Classes are reference types and structs are value types

21. What are constructors in C#, and how do they differ from other methods?

A constructor is a special method of the class.

• The constructor of a class must have the same name as the class name in which it resides.
• A constructor can not be abstract, final, and Synchronized.
• Within a class, we can create only one static constructor.
• A constructor doesn’t have any return type, not even void.
• A static constructor cannot be a parameterized constructor.
• A class can have any number of constructors.
  

Creating Objects

22. Explain how objects and classes are created in C#.

A class defines the blueprint or template for creating objects while an object is an instance of a class. In other words, a class defines the fields(variables) and methods(member functions which define actions) of an object. An object is an instance of those fields(variables) and methods.

Creating objects:

23. Elaborate on the implementation of encapsulation.

Encapsulation is one of the four fundamental principles of object-oriented programming (OOP), alongside inheritance, polymorphism, and abstraction. It refers to wrapping data and corresponding methods into a single unit or class.

Encapsulation in C# can be implemented by using access modifiers like protected, and public-private. These access modifiers control the visibility and accessibility of class members.

24. Does support multiple inheritance in C#

Basically C# does not support multiple inheritance. A class cannot directly inherit from multiple classes. However, it supports multiple interface inheritance, enabling a class to implement multiple interfaces.

25. What is called by value in C#?

In C#, call by value means that when you pass an argument to a method, the method receives a copy of the argument’s value. As a result, any modifications made to the parameter inside the method do not impact the original variable outside the method.

26. What is called by reference in C#?

When a method is called by reference using the ref keyword in C#, the method can modify the original variable directly. Changes made to the parameter inside the method affect the original variable outside the method.

27. What is static polymorphism in C# and how is it achieved?

Static polymorphism, also known as early binding or compile-time polymorphism, occurs when a function is linked with an object during compile time. In C#, static polymorphism is achieved through function overloading and operator overloading.

Method overloading is defining multiple methods with the same name but different parameters wthin the same class.

28. What is dynamic polymorphism in C#, and how does it relate to abstract classes and methods? Provide an example.

Dynamic polymorphism (also known as runtime polymorphism) specifically refers to the ability of a method to exhibit different behaviors at runtime based on the actual object . This is achieved through method overriding in inheritance, where a base class declares a method as virtual, and derived classes override it to provide specific implementations.

29.What is an interface in C#, and how does it differ from an abstract class? Provide an example demonstrating the use of an interface.

Characteristics of interfaces:

No Implementation: Interfaces define methods and properties without providing implementation. Classes that implement an interface must provide the implementation.

Multiple Inheritance: A class can implement multiple interfaces, allowing for multiple inheritance of method signatures.

No Constructors: Interfaces cannot have constructors.

Explore the difference between abstract classes and interfaces:

30. What are the pros and cons of using inheritance in C#?

Inheritance creates a child-parent relationship between two classes. After implementing inheritance, the child class can automatically obtain the properties and methods of the parent class.

Define a base(Parent) class :

Define derived(child) class :

Create Objects:

Pros:

Code Reusability: Inheritance allows us to reuse existing code by inheriting
properties and methods from an existing class.
Code Maintenance: Inheritance makes code maintenance easier by
allowing us to modify the base class and have the changes automatically
reflected in the derived classes.
Code Organization: Inheritance improves code organization by grouping
related classes together in a hierarchical structure

Cons:

Tight Coupling: Inheritance creates a tight coupling between the base class
and the derived class, which can make the code more difficult to maintain.

Complexity: Inheritance can increase the complexity of the code by
introducing additional levels of abstraction

In this post, I explored 30 essential questions that define the core concepts of C# and .NET development.

What’s Next?

Now you have a greater understanding of the .NET core framework, now you are ready to go for deeper tech theories. With that, you’ll be interested in reading the following technologies also.

• Mastering React JS
• Master Class for Azure Fundamentals