Topics Covered:

• Syntax
• C# Grammar
• Vocabulary
• Methods are Verbs
• Variables, Fields and Properties
• Data Types
• Identifiers
• Data Types
• Classes and Methods

Syntax

It is a set of rules on how to make a running program in that language.

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Console.WriteLine("C# is awesome");

C# Grammar

C# grammar includes:

• Statements
• Blocks

Statements

Like a Sentence ends with fullstop. C# Statement ends with semicolon; An Statement consists of multiple variables and expressions. Example:

Console.WriteLine(Environment.CurrentDirectory);

Blocks

Like a paragraph starting with new line. A block of code is indicated with curly braces {} Block Starts with : deceleration followed by curly braces.

Example:

• namespaces
• classes
• loops
• methods

using System;

class Foo
{
    void Main()
    {
        Console.WriteLine(Environment.Version);
    }
}

Vocabulary

C# vocabulary consists of:

• Keywords
• Symbols
• Characters
• Types

int implicitVariable = 1997;
var explicitVariable = 1997;

Methods are Verbs

Verb are action words like eat and sleep. In C# method is action words.

// 3 versions of WriteLine
Console.WriteLine();
Console.WriteLine("version 1");
Console.WriteLine($"{2:D} days left");

Types, Variables, Fields and Properties

Type

It is used to categorize things. Every Type can be categorized as class, struct, enum, interface and delegate. Example: Animal

Field

These are the properties. Example: Head of animal

Variables

Noun refering to specific object. Example: Lucy name of dog.

A variable can either be defined by specifying their type:

• Implicitly
• Explicitly

Literals

literal is a chunk of code that is literally or precisely is as it is written. Example of String Literal: “C# is awesome”

Identifiers

Identifier allows us to reference to something existing in the code element. Example: Console and Writeline

Data Types:

Set of values with similar characteristics. Characteristics:

• Name
• Size
• Default Value

Types:

• Integer (sbyte, short, int, long

  byte, ushort, uint, ulong

  nint, nuint)

• Real floating-point (float, double)
• Real type with decimal precision (decimal)
• Boolean (bool)
• Character (char)
• String (string)
• Object (object)
• Dynamic (dynamic)

//numbers
int x = 100;
var y = 200.0011f;
decimal z = 300;

//Observing the size and ranges
Console.WriteLine($"int uses {sizeof(int)} bytes and can store the values from {int.MinValue:N0} to {int.MaxValue:N0}.");

//double trouble
double numOne = 1.1;
double numTwo = 2.2;

if(numOne+numTwo == 3.3)
{
    Console.WriteLine($"{numOne} + {numTwo} equals to 3.3");
}
else
{
    Console.WriteLine($"{numOne} + {numTwo} doesn't equals to 3.3");
}
//For accuracy use decimal rather than double


//bool
var whatDoYouThink = false;

//char
char letter = 'A';

//literal strings
string firstName = "firstName";
Console.WriteLine(letter);

//VERBATIM STRING
 var firstString = "\\\\server\\folder\\file.cs";
 Console.WriteLine("first verbatam string:" + firstString);
 Console.WriteLine(@"\\server\folder\file.cs");
 Console.WriteLine(@"this is a 
multiline
             string");

//Interpolated string
Console.WriteLine($"{letter} {firstName}");

Digit Separators: Underscore character _ can be used as a digit separator. As 1_00_000.

//objects are special type of that can store any kind of data [flexible but messier code and poor performance]
object anObject = "himalaya";
// Console.WriteLine($"{anObject} has {anObject.Length} characters");
Console.WriteLine($"{anObject} has {((string)anObject).Length} characters");

//DYNAMIC TYPES - [Flexible than object but comes with the cost of performance]
//dynamic
dynamic life = "tentative";

Classes and Methods

Class keyword is used to define a class and new is used to instantiate it’s objects. For understanding: Class is like a person in a team. A whole work is divided for each person and they perform the specified task to complete the job.

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class ClassName{
    //body
}

new ClassName();

Classes contains:

• Data

• Methods (tasks they need to perform)

• Functions within classes is termed as methods
• Methods can have 0 - many parameters passed to it whose type must be explicitly defined.
• Values must be returned using return keyword.
• To be able to be accessed from other files, method must be made public.
• Method are invoked/called using .

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namespace Application
{
    class Program
    {
        static void Main(string[] args)
        {
            ClassAdd twoClass = new();
            Console.WriteLine(twoClass.Add(5, 2));
        }
    }
}
class ClassAdd{
    public int Add(int x, int y)
    {
        return x + y;
    }
}