C# Basics

C#, a programming language used to develop applications of various types and it is read as CSharp. Which is an Object-oriented developed by Microsoft. Anders Hejlsberg is the lead architect for C#.Net.

C# is designed for CLI, which has executable code and run-time environment that permit use of various high-level languages on various platforms and architectures.

• C# is general purpose language which can produce efficient programs. 
• C# program can be compiled on different platforms. 
• C is a part of dot Net Framework. 

It can be used to create windows applications, web applications, and Web services. Visual Studio is the best IDE for writing C# programs.

Every C# program consists of a Namespace, Class, Main method, Methods, Statements, Comments etc. 

Take a look at the basic program: 

using System;

namespace first_namespace
{
    class first_program
    {
        static void Main()
        {
            Console.WriteLine("Csharp World");
        }
    }
}

Output: Csharp World

Extension of a C# program is ".cs".

Keyword "using" is to include namespaces. Any C# program can have one or more using statements in it. 

Syntax for calling a namespace:

using <namespace>;

A namespace is a group of classes and methods. 

In the above example we have created a namespace with name first_namespace. 

Syntax: 

namespace namespace_name

{

   class class_name

   {

         //members

   }

}

If we write System.Console.WriteLine("Csharp World"); then for this line of code we don't require to call System namespace with using keyword.

namespace first_namespace
{
    class first_program
    {
        static void Main()
        {
            System.Console.WriteLine("Csharp World 2");
        }
    }
}
Output: Csharp World 2

In the above example we did not write using keyword because we prefixed System namespace with Console class directly.

A class in C# is used to create a custom type or template, it allows us to create objects. Class can have members like objects, variables, and methods in it. A class is a reference type.

   [<Modifiers>] class class_name

   {

         //members;

   }

Every statement and an expression should end with a semicolon(;).

CSharp is case-sensitive, all the predefined libraries are implemented in "Proper Case". Proper Case means the first character of every word is Capital/Upper Case. 

In C#, all the keywords are in lower case.

Syntax:

static <void/int> Main([<String[] args>])

{

 // statements or code. 

}

• Return type of Main method can be void or int only and Main method should be declared as static. 
• Main method is the entry point of all C# programs. 

Comments:

We use //(double forward slash) to indicate Single line comments. 

Example 1:

static <void/int> Main([<String[] args>])

{

 // statements or code. 

}

We use / * */ for Multi-line comments:

Example 2:

/* statements..

    statements..

    statements..

*/

The text inside the comments will not be excluded, they're only to give information. 

C# Primitive Data Types:

bool

Signed integral:

•   sbyte
•   short 
•   int 
•   long

Unsinged intergral:

•   byte
•   ushort
•   uint
•   ulong

floating point:

•   float
•   double

char

decimal

List of Keywords in C#:

as                abstract           base           bool

break           byte                catch          case

char             checked          clonst         class

continue      decimal           default        delegate

do               double             else            enum

event           explicit           extern         false

finally          fixed               for              float

foreach        goto                if                implicit

in                 int                  interface     internal

is                 long                lock            namespace

new             null                 object         operator

out              override          params        private

public          protected        ref              readonly

return          sbyte              sealed         short

sizeof           stackalloc       static          string

struct           switch            this             throw

try               true                typeof         uint

ulong           unchecked       ushort         unsafe      

using           using static      virtual         volatile

void             while

Operators in C#: 

Arithmetic                              :  +, -, *, /, %

Assignment                             : =, +=, -=, *=, /=, %=

Comparison                            : ==, !=, <, <=, >, >=, is, as, Like

Concatenation                        : +

Increment and Decrements     : ++, --

Logical                                   : &&, ||, ^