Overview of Object-Oriented Programming Concepts

OOP Paradigm

Programming Paradigm based on object and class

Procedural Programming

Sequence of Instructions to be executed.

Spaghetti Codes

Program Jumps over the place and its difficult to follow.

High Level Programming Languages

Languages like java, C#, JavaScript etc.

Class

Is a container that has data that called attributes and functions that called methods.

Encapsulation

Bundling of data and methods into a single unit.

Inheritance

A mechanism that allows a child class to inherit properties from its parent Class.

Polymorphism

Is the ability of an object to take on many forms.

Abstraction

Hides Complexity, Property and Methods.

Data Types

a particular kind of data item, as defined by the values it can take, the programming language used, or the operations that can be performed on it.

Value type

Data types that holds a value within its own memory.

Reference Data Type

Data types that contains a pointer to another memory.

Variables

Used to store and manipulate data.

Declaration

Data must be declared before use.

Initialization

Giving a variable an initial value.

Scope

Determines where in the code variables can be accessed.

Lifetime

Duration during which it exists on the memory.

Mutability

Mutable or not immutable.

Naming Convention

Rules in writing a name in programming.

Type Inference

Automatically determined by the compiler based on assigned value.

Nullability

Nullable reference types.

Value Assignment

The process of storing a value in a variable's memory location.

Constant

A data item that whose value cannot be changed during program execution.

Operators

Used in mathematical or logical manipulations.

Assignment Operators

Used to assign and update and store values to variables.

Arithmetic Operators

Used to perform Mathematical Operations on numeric Values.

Relational Operators

Used to compare two values or expression and return a boolean result.

Logical Operators

Used to perform logical Operations on boolean values and allows combine and modify conditions in complex ways.

Expression

Operators that can be evaluated to single value, Combination of operands.

Comments

Essential for improving code readability.

Control Structures

A way to specify the flow of control in any algorithm or program.

Sequential Logic

It follows a serial or sequence flow.

Selection Logic

Allows one set of statements to be executed if a condition is true and another set of actions to be executed if false.

Iteration Logic

Employs a loop which involves a repeat statement.

For()

Repeats a block of code a specific number of times.

While()

Repeats a block of code as long as a given condition is true.

Public

Can be directly called once the object is created.

Private

Called within a method and it is not visible when object is created.

Protected

Can only be accessed by the class itself and cannot be changed.

Methods

a block of code that contains a series of statements also called functions

Access Modifiers

keywords that are used in order to specify the accessibility of methods

Void

a return type that means this method doesn't have a return value

Method Overload

C# allows multiple method to have the same name but with different signatures

Static Methods

Can be called without creating an object of the class

Optional Parameters

C# allows specifying default values for parameters which make them optional when calling the method

Round()

rounds a single number to the nearest Integer or specified decimal places

Sqrt()

returns the square root of a number

Pow()

returns the value of x to the power of y

Abs()

returns absolute value of a number

Length (String)

get the number of characters in a string

ToUpper/Lower

Converts a string to upper or lower case format

Contains()

check if the string is contains a specified substring

Replace()

Replace all occurrences of a substring with another string

Substring ()

retrieves a portion of a string

Length (Array)

returns number of elements in the array

Sort()

arranges the elements in ascending order

IndexOf()

Returns the index of the first occurrence of an element

ToInt, ToDouble, ToString()

Converts an object to the specified type

Parse()

Converts string to a specific type

Strings

Collection of Characters

String Interpolation

using the symbol $ before a string allows to embed expression directly in a string

String Method

methods that Helps manipulate and analyze String data

String Comparison

Compare String using method like Equals, Compare, and Compare Ordinal for various types of strings

String Formatting

using method like string.format or interpolated strings for more complex formatting task

Null String

the variables does not point to any String object, while an empty String is a valid string with no characters

Type casting

it's when you assign a value of one data type to another type

Explicit Typecasting

Converting a larger type to a smaller type

Implicit Typecasting

Converting a smaller type to a larger type

Constructors

special methods in C# that will invoke automatically when an object class is created

Default Constructors

You can set an initial value of the class itself

Polymorphism Constructors

Implementing Constructors in different ways

Copy Constructors

Constructors that copy itself

Private Constructors

Preventing to implement this specific constructor, while implementing Encapsulation

Static Constructor

You can invoke this constructor Once

Errors

Mostly happen at compile time, occurs when you violate the rules of a programming language

Exception

Occurs at run time, syntactically correct but encounters an unexpected condition during execution

Try

This is where to place the code that may potentially throws an exception

Catch

Specifies the type of exception and if an exception occurs the code within the catch block will be executed

ex

Variable that holds a reference to the caught exception

finally

Executed regardless of whether an exception was thrown.

Event Driven

It occurs when the user interacts with a GUI object.

Event-Driven Programming

It fosters the dynamic interaction between users and computers.

Windows Forms

Is a Graphical User Interface (GUI) class library, to provide an easier interface to develop the application.

Editor Window or Main Window

Here, you will work with forms and code editing, double click the form then it will open the code for that.

Properties Window

This window is used to change the different properties of the selected item in the Solution Explorer.

Solution Explorer Window

It is used to navigate between all items in solution.

Windows Forms framework

Provides controls that developers can use to build applications.

Windows Forms applications

Versatile and can be used to create various types of applications such as data entry, management, and reporting applications, as well as games and multimedia applications.

Software development framework

Developed by Microsoft, provides a runtime environment and a set of libraries and tools for building and running applications on Windows operating systems.

Common Language Runtime (CLR)

Responsible for managing the execution of code written in any of the supported languages.

.NET Framework Class Library

Pre-built functions and classes that can be used to create a wide range of applications.

History of .Network Framework

Designed and developed by Microsoft. First version of the .Net framework was 1.0 (Year = 2002).

.Net Framework

To develop Form-based applications, Web-based applications, and Web services.

.Net platform

Includes VB.Net, C#, etc., used to build applications for Windows, phones, web, etc.

.Net Phase I

OLE Technology - Early 1990's: Interprocess Communication.

.Net Phase II

COM Technology
1995: Intermodule Communication.

.Net Phase III

Late 1990's: Intersite Communication.

OLE Technology

OLE (Object Linking and Embedding) to link elements from different applications with each other.

Common Object Model (COM) Technology

COM (Common Object Model) enables various software components to communicate.

.NET Technology

Collection or set of technologies to develop windows and web applications, launched in Feb. 2002.