
Delve into .NET development with C#, covering programming fundamentals, object-oriented principles, exception handling, and multithreading. Gain hands-on experience to build cross-platform applications effectively.

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.NET is Microsoft’s free and open source framework for developing native software applications on Linux, macOS, and Windows. The power of cross-platform development allows developers to design, code, and run programs on a wide array of platforms.

This course is an introduction to developing .NET applications using C#. You’ll start start with a comprehensive review of C# and computer programming fundamentals: data types, conditionals, loops, methods, and more. You’ll then review the basics of object-oriented programming before diving into methods, exception handling, delegation, and events. With this foundation, you’ll continue building interfaces, collections, database operations, and multithreading. You’ll wrap up with process improvements using dynamic binding, garbage collection, and unmanaged resources.

By the end of this course, you’ll have hands-on experience with C# and .NET, and be ready to build applications using object-oriented programming principles on almost any platform.

Mastering C# and .NET

# The `if-else` statement

**Conditional statements** are a basic component of many programming languages. They control program flow, depending on given conditions.

Consider the following scenario. We want to build a program that determines whether a user is an adult by checking their age. If the user is `18` or older, then they’re an adult.

Let’s first create a variable to obtain the user’s age.

```C#
Console.Write("What is your age? ");
int age = Convert.ToInt32(Console.ReadLine());
```

We now perform a check. If `age` is greater than `18`, then we print `“You are an adult!”` Otherwise, we print `“You are not yet an adult.”`

Such checks can be done using the `if-else` statement in C#. The basic syntax is as follows:

```C#
if (condition)
{
	// Actions to be executed if the condition is true
}
else 
{
	// Actions to be executed if the condition is false
}
```

The condition, in this context, is simply a `bool` value that holds either `true` or `false`:

using System;

namespace Conditionals
{
    class Program
    {
        static void Main(string[] args)
        {
            bool isAdult = true;

            if (isAdult)
            {
                Console.WriteLine("You are an adult!");
            }
            else
            {
                Console.WriteLine("You are not yet an adult.");
            }
        }
    }
}

Change the value of `isAdult` to `false` and execute the program once again. This time, the output is different.

Manually assigning value to a `bool` variable isn’t useful if we want our program to be dynamic. There are various operators that return a `bool` value that can be used in checks.


## Comparison operators

**Comparison operations** compare two operands and return a `bool` value: `true` if the expression is true, or `false` if the expression is false.


| Comparison operator | Definition |
| --------------------- | :---------- |
| `==` | This is an equality check. It returns `true` if the operands are equal to each other. Otherwise, it returns `false`. |
| `!=` | This is an inequality check. Itreturns `true` if the operands aren’t equal to each other. Otherwise, it returns `false`. |
| `>` | This returns `true` if the first operand is greater than the second operand. Otherwise, it returns `false`. |
| `<` | This returns `true` if the first operand is less than the second operand. Otherwise, it returns `false`. |
| `>=` | This returns `true` if the first operand is greater than or equal to the second operand. Otherwise, it returns `false`. |
| `<=` | This returns `true` if the first operand is less than or equal to the second operand. Otherwise, it returns `false`. |

Equipped with this knowledge of comparison operators, we can now finish our program. When our program needs several conditions and each condition should lead to a different set of actions, we can add `else if` blocks:

Use conditional statements in C# programs.

Getting Started

C# Programming Basics

Classes and OOP

Classes and OOP II

Exception Handling

First Assessment

Delegates and Events

Interfaces

Additional Features

Collections

LINQ

Working with Strings

Working with Dates and Time

Multithreading and Asynchronous Programming

Reflection

Dynamic Binding

Garbage Collection and Unmanaged Resources

Final Assessment

Next Steps

Appendix

Conditionals

The `if-else` statement

First Assessment

Final Assessment

Conditionals

The if-else statement

The `if-else` statement