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# Understanding Fundamental Concepts in πͺ#

## Default Values, Conversions, Call by Value/Reference, Class Method, Instance Method - YouTube

π₯ C# Tutorial for Beginners: Understanding Default Values, Conversions, Call by Value/Reference, Class Method, Instance Method π₯Hey there, fellow code wiza...

## Introduction

Hello, fellow programmers! I'm πΌπΎ, and today we'll explore some fundamental concepts of πͺ#. Whether you're new to programming or refreshing your skills, this guide will help you grasp key aspects of πͺ#. So, grab your favourite beverage β, and let's get started!

## Default Values

Let's begin with default values in πͺ#. You might wonder why the default value of a string is null or why an int defaults to zero. Here's a quick explanation:

In the digital world, everything is represented by 0s and 1s. A zero signifies no voltage, while a one represents approximately +5 voltage. In a CPU, there are numerous pins, and the motherboard sends either zero or one voltage to these pins. When it's zero, no energy is consumed, but when it's one, energy is used.

When a variable is created with a default value, it aims to save energy. For instance, if the default value of an `int` is `zero`, it doesn't consume any voltage power when initiated because it would convert to something like 0000, and the CPU wouldnβt consume any energy for processing this variable. Similarly, the default value of a `Boolean` is `false`, meaning no voltage power is used. This principle helps in efficient power usage across your computer's operations. The same applies to a string variable; for instance, a string variable called address initially points to nothing, which is null. If you try to get the address length without any initialization, you'll get a null exception.

## Conversions

Next, let's discuss conversions in πͺ#. There are different ways to convert data types: implicit, explicit, boxing, unboxing, and casting. These concepts may sound confusing, but we'll focus on implicit and explicit conversions for now.

## Implicit Conversion

This happens when the compiler automatically knows how to convert one type to another without losing data. For instance, converting an int to a long is safe because a long can hold all possible int values. If you convert an int to a long, there is no error or warning because the compiler knows it's safe.

## Explicit Conversion

This requires you to explicitly instruct the compiler to convert the value, often using a cast. This is necessary when thereβs a risk of data loss, such as converting a `long` to an `int`. For example, if you try to convert a `long` to an `int`, the compiler will throw an error because it cannot implicitly convert long to int due to potential data loss. You must use explicit conversion and accept the risk of losing data.

In all conversion scenarios, if the compiler can convert the values, it is an implicit conversion. If it cannot, then it is an explicit conversion. So far, we have only discussed value type conversion, which occurs at the stack. In future discussions, we will explore boxing and unboxing, crucial for converting between value types and reference types.

## Call by Value, Call by Reference

Let's explore call by value and call by reference, essential concepts when passing variables to methods.

## Call by Value

When you pass a variable by value, a copy of the variable is sent to the method. Any changes made to the variable inside the method won't affect the original variable. For example, if you have a variable named Number and a method to alter its value, the changes inside the method won't affect the original variable outside the method.

## Call by Reference

Using the `ref` keyword ensures the method works directly with the original variable, allowing changes to be reflected outside the method. Instead of creating a new variable, the method works with the original variable, and any changes made inside the method will affect the original variable.

## Class Method vs. Instance Method

Lastly, let's discuss class methods (static methods) versus instance methods.

## Instance Methods

These are associated with an instance of a class. Each object created from the class has its own copy of the instance methods. For example, if we create another instance, it will be allocated somewhere else in the memory with its own set of instance methods.

## Static Methods

These belong to the class itself rather than any object instance. They are shared across all instances and can be accessed without creating an instance of the class. Static methods are stored in a place called *HFH * (High-Frequency Heap) at the bottom of the heap. Being static indicates that it has all the necessary information and does not rely on other services or resources.

In multi-threaded environments, instance methods are safer because each thread has its own space and allocations. However, static methods are shared between threads, which can lead to unexpected errors if shared resources are modified by multiple threads.

## Summary

In this guide, we've covered the fundamental concepts of πͺ#, including default values, conversions, call by value, call by reference, and the differences between class methods and instance methods. Understanding these basics is crucial for efficient and effective πͺ# programming. As you continue to learn and practice, these concepts will become second nature, enhancing your coding skills and knowledge. Happy coding! π₯οΈβ¨