SDP imp Notes (VipJet)

1. Ecilipse installation and Features

Eclipse is an integrated development environment (IDE) used for developing software. It is written in Java and can be used on a variety of platforms, including Windows, macOS, and Linux. Eclipse is a free and open-source software, and is one of the most popular IDEs for Java development.

To install Eclipse, you can download the installer from the Eclipse website. The installer is available for Windows, macOS, and Linux. Once you have downloaded the installer, run it to begin the installation process. The installation process is straightforward and should only take a few minutes to complete.

Once Eclipse is installed, you can launch it by clicking on the Eclipse icon on your desktop. When Eclipse starts, you will be presented with a welcome screen. The welcome screen allows you to create a new project or open an existing project.

Here are some additional details about the installation process:

• The Eclipse installer requires a Java Runtime Environment (JRE) to be installed on your computer. If you do not have a JRE installed, the installer will prompt you to install one.
• The Eclipse installer allows you to choose the features that you want to install. This can be helpful if you only need a subset of the features that Eclipse offers.
• The Eclipse installer creates a default workspace for your Eclipse projects. You can change the location of the workspace if you want.

Features of Eclipse:

• Code editor: The Eclipse code editor is a powerful tool that allows you to write and edit Java code. The code editor includes features such as syntax highlighting, code completion, and error checking.
• Debugger: The Eclipse debugger allows you to step through your Java code line by line. This can be helpful for debugging your code and finding errors.
• Package explorer: The Package Explorer allows you to view the structure of your Java project. This can be helpful for navigating your project and finding the files you need.
• Console: The Console allows you to run Java code and view the output. This can be helpful for testing your code and debugging errors.
• Wizards: The Wizards in Eclipse allow you to create new Java projects and other types of files. This can be helpful for getting started with Eclipse and creating new projects.
• Extensions: Eclipse is extensible, which means that you can add new features to it by installing extensions. There are many extensions available for Eclipse, including extensions for development, testing, and deployment.

Eclipse is a powerful IDE that can be used for developing Java software. It has a wide range of features that can help you write, debug, and deploy your Java code.

2. AVD installation

An Android Virtual Device (AVD) is a software emulation of an Android device that runs on your computer. You can use an AVD to test your Android app on a variety of devices and configurations without having to own or borrow physical devices.

To install an AVD, you need to have the Android SDK installed on your computer. Once you have the SDK installed, you can follow these steps to create an AVD:

1. Open the Android Virtual Device Manager (AVD Manager).
2. Click the "Create Virtual Device" button.
3. In the "Select Hardware" window, select the hardware profile for your AVD.
4. In the "System Image" window, select the system image for your AVD.
5. Click the "Next" button.
6. In the "Target Android version" window, select the target Android version for your AVD.
7. Click the "Finish" button.

The AVD Manager will create the AVD and start it. Once the AVD is started, you can connect to it using Android Studio or the Android Debug Bridge (ADB).

Here are some additional details about AVD installation:

• The AVD Manager requires the Android SDK to be installed on your computer. If you do not have the SDK installed, the AVD Manager will prompt you to install it.
• The AVD Manager allows you to choose the hardware profile and system image for your AVD. The hardware profile determines the physical characteristics of your AVD, such as the screen size, resolution, and processor type. The system image determines the Android version and software that is installed on your AVD.
• The AVD Manager creates a default AVD configuration for you. You can change the default configuration or create new configurations for your AVDs.
• You can start, stop, and restart your AVDs using the AVD Manager.
• You can connect to your AVDs using Android Studio or the ADB. Once you are connected to an AVD, you can run your Android app on it.

3. Explain Android SDK

The Android Software Development Kit (SDK) is a set of tools that developers use to build Android apps. It includes a variety of components, such as:

• The Android platform: This is the core software that runs on Android devices. It includes the operating system, libraries, and APIs that developers need to build their apps.
• The Android Studio IDE: This is a powerful integrated development environment (IDE) that makes it easy to write, edit, and debug Android code.
• The Android Emulator: This is a virtual device that allows developers to test their apps on a variety of Android devices without having to own them.
• The Android Debug Bridge (ADB): This is a command-line tool that allows developers to interact with Android devices and emulators.

The Android SDK is available for free from the Google Developer website. It is a valuable resource for any developer who wants to build Android apps.

Here are some of the benefits of using the Android SDK:

• It provides a comprehensive set of tools that developers need to build Android apps.
• It is easy to use and learn.
• It is supported by a large community of developers.
• It is constantly being updated with new features and improvements.

If you are interested in developing Android apps, the Android SDK is a great place to start.

Here are some additional resources that you may find helpful:

• The Android Developers website: This website provides a wealth of information about Android development, including tutorials, documentation, and sample code.
• The Android Studio documentation: This documentation provides detailed instructions on how to use Android Studio.
• The Android Debug Bridge documentation: This documentation provides information on how to use the ADB command-line tool.

4. Mobile Technologies

explanation of some of the most common mobile technologies:

• GSM (Global System for Mobile Communications) is a digital cellular network technology that is used by over 2 billion people worldwide. GSM is a 2G technology, which means that it provides voice and text messaging services.
• 1G (First Generation) refers to the first generation of cellular networks, which were analog and provided only voice services. 1G networks are no longer in use.
• 2G (Second Generation) refers to the second generation of cellular networks, which are digital and provide voice, text messaging, and limited data services. 2G networks are still in use in many parts of the world.
• 3G (Third Generation) refers to the third generation of cellular networks, which provide faster data speeds than 2G networks. 3G networks are used for streaming video, downloading music, and other data-intensive activities.
• HSDPA/HSUPA (High Speed Downlink Packet Access/High Speed Uplink Packet Access) are two technologies that are used to improve the data speeds of 3G networks. HSDPA allows for faster downloads, while HSUPA allows for faster uploads.
• UMTS (Universal Mobile Telecommunications System) is a 3G standard that is used by many countries around the world. UMTS is based on the GSM standard, but it offers faster data speeds.
• EV-DO (Evolution-Data Optimized) is a 3G standard that is used by some carriers in the United States. EV-DO offers faster data speeds than UMTS.
• 4G (Fourth Generation) refers to the fourth generation of cellular networks, which offer even faster data speeds than 3G networks. 4G networks are used for streaming high-definition video, gaming, and other data-intensive activities.
• LTE (Long Term Evolution) is a 4G standard that is used by many carriers around the world. LTE offers the fastest data speeds of any mobile technology currently available.
• CDMA (Code Division Multiple Access) is a different type of cellular technology than GSM. CDMA is used by some carriers in the United States, but it is not as widely used as GSM.

5. Android vs IOS

6. Features of Android

Here are some of the key features of Android:

• Open source: Android is an open-source operating system, which means that it is free to use and modify. This has led to a large community of developers creating apps and customizations for Android devices.
• Customization: Android is a highly customizable operating system. Users can change the look and feel of their device by installing different themes, launchers, and widgets. They can also install apps from the Google Play Store or other third-party sources.
• Security: Android includes a number of security features, such as a built-in firewall, encryption, and a permission system. These features help to protect users from malware and other security threats.
• Accessibility: Android is designed to be accessible to users with disabilities. It includes a number of features, such as TalkBack, that help users with vision impairments, and Switch Access, that helps users with mobility impairments.
• Multitasking: Android supports multitasking, which means that users can run multiple apps at the same time. This can be useful for tasks such as listening to music while browsing the web or checking email while playing a game.
• Connectivity: Android devices can connect to a variety of networks, including Wi-Fi, cellular networks, and Bluetooth. This allows users to stay connected to the internet, other devices, and other users.
• App support: The Google Play Store is the official app store for Android devices. It offers a wide variety of apps, including games, productivity apps, and social media apps. Users can also install apps from third-party sources, such as the Amazon Appstore.
• Updates: Android is a constantly evolving operating system. Google releases new versions of Android on a regular basis, and these updates often include new features and security improvements.

7. Architecture of Android

Android is a layered architecture, which means that it is made up of a number of layers that build on top of each other. The layers are:

• Linux Kernel: The Linux kernel is the core of the Android operating system. It provides the basic services that all other layers rely on, such as memory management, process management, and device drivers.
• Hardware Abstraction Layer (HAL): The HAL provides a layer of abstraction between the Android software and the underlying hardware. This allows the Android software to be used on a variety of different hardware platforms.
• Android Runtime (ART): ART is a new runtime environment that is used to run Android apps. ART is more efficient than the previous runtime environment, Dalvik, and it also provides better security features.
• Android Framework: The Android framework is a set of APIs that developers use to build Android apps. The framework provides classes for things like graphics, user input, networking, and storage.
• Applications: Applications are the software that users interact with on their Android devices. Applications can be anything from games to productivity tools to social media apps.

The Android architecture is designed to be modular and flexible, which allows it to be adapted to a wide range of devices and use cases. The modularity of the architecture also makes it easier for developers to build and maintain Android apps.

Here is a diagram that shows the Android architecture:

The diagram shows how the different layers of the Android architecture interact with each other. The Linux kernel is at the bottom of the diagram, and it provides the basic services that all other layers rely on. The HAL sits on top of the Linux kernel, and it provides a layer of abstraction between the Android software and the underlying hardware. ART sits on top of the HAL, and it provides a more efficient and secure runtime environment for Android apps. The Android framework sits on top of ART, and it provides a set of APIs that developers use to build Android apps. Applications sit on top of the Android framework, and they are the software that users interact with on their Android devices.

The Android architecture is a complex system, but it is designed to be flexible and adaptable. This allows it to be used on a wide range of devices and for a wide range of purposes.

8. Installing Android IDE

To install an Android Integrated Development Environment (IDE), you can follow these general steps:

1. Choose an Android IDE: There are several popular Android IDEs available, such as Android Studio, Eclipse with the Android Development Tools (ADT) plugin, and IntelliJ IDEA with the Android plugin. Android Studio is the most widely used and recommended IDE for Android development.
2. Download the IDE: Visit the official website of the chosen IDE and download the installer package suitable for your operating system (Windows, macOS, or Linux).
3. Run the installer: Once the download is complete, run the installer package and follow the on-screen instructions. The installation process may vary slightly depending on the IDE you chose.
4. Set up Android SDK: The IDE will prompt you to set up the Android Software Development Kit (SDK) if it's not already installed on your system. The SDK contains tools, libraries, and system images necessary for Android app development. The IDE will typically provide an option to download and install the SDK components automatically.
5. Configure the IDE: After the installation and SDK setup, you may need to configure the IDE by specifying the JDK (Java Development Kit) location. The IDE will guide you through this process.
6. Install additional components (if required): Depending on your development needs, you may need to install additional components or plugins. For example, if you're using Eclipse, you'll need to install the ADT plugin to enable Android development features.
7. Start the IDE: Once the installation and configuration are complete, you can launch the IDE. Android Studio, for instance, can be started by clicking on its icon in the application launcher or by running the executable file.
8. Set up a new project: The IDE's welcome screen typically provides options to create a new project or import an existing one. Follow the instructions to set up a new Android project.
9. Emulator setup: To run and test your Android apps, you can set up virtual devices (emulators) within the IDE. This allows you to simulate various Android device configurations. The IDE usually provides tools to manage and create virtual devices.
10. Start developing: With the IDE installed and set up, you're ready to start developing Android applications. You can create new Java or Kotlin files, design user interfaces, write code, and utilize the tools and features offered by the IDE to build your app.

9. Features of Android Studio (ide)

1. Project Structure: Android Studio provides a well-organized project structure where you can manage your source code, resources, and dependencies. It also includes built-in tools for version control, such as Git.
2. Code Editor: The IDE offers a powerful code editor with features like syntax highlighting, code completion, and code analysis. It supports various programming languages, including Java and Kotlin, which are commonly used for Android development.
3. Layout Editor: Android Studio includes a visual layout editor that allows you to design your app's user interface using a drag-and-drop interface. You can preview the layouts on different screen sizes and orientations.
4. Android Virtual Device Manager: This feature allows you to create and manage virtual devices (emulators) for testing your app on various Android configurations. You can simulate different device characteristics, such as screen size, resolution, and hardware capabilities.
5. Build and Run: Android Studio provides a streamlined build and run process, allowing you to compile your code, package it into an APK (Android Package), and deploy it to a connected device or emulator with a single click.
6. Debugging Tools: The IDE includes a comprehensive set of debugging tools to help you identify and fix issues in your application. You can set breakpoints, inspect variables, step through code execution, and monitor logs.
7. Profiling Tools: Android Studio offers performance profiling tools to analyze your app's CPU, memory, and network usage. These tools help optimize your app's performance and identify bottlenecks.
8. Device File Explorer: You can access the file system of connected devices or emulators using the Device File Explorer. This allows you to view, copy, and delete files on the device, which can be useful for debugging and data management.
9. Android Asset Studio: This built-in tool provides a collection of utilities to generate icons, app themes, and other graphical resources. It helps you create visually appealing and consistent designs for your app.

10. Features of ios

• Siri: Siri is Apple's voice assistant that can be used to control your iPhone, iPad, or iPod touch hands-free. You can use Siri to make calls, send messages, set alarms, get directions, and more.
• Face ID: Face ID is a facial recognition feature that allows you to unlock your iPhone, iPad, or iPod touch, authorize payments, and sign in to apps without having to enter a passcode.
• Touch ID: Touch ID is a fingerprint sensor that allows you to unlock your iPhone, iPad, or iPod touch, authorize payments, and sign in to apps without having to enter a passcode.
• iCloud: iCloud is Apple's cloud storage service that allows you to store your photos, videos, documents, and other files online. You can access your iCloud files from any device that is signed in to your iCloud account.
• App Store: The App Store is a digital distribution platform that allows you to download and install apps on your iPhone, iPad, or iPod touch. The App Store has a wide variety of apps, including games, productivity apps, social media apps, and more.
• Safari: Safari is Apple's web browser that is pre-installed on all iOS devices. Safari is a fast and secure web browser that supports a variety of features, including extensions, bookmarks, and private browsing.
• Maps: Maps is Apple's built-in navigation app that allows you to get directions, find businesses, and view maps of different locations. Maps also supports features such as live traffic updates and public transit directions.
• Photos: Photos is Apple's built-in photo gallery app that allows you to view, edit, and share your photos. Photos also includes features such as facial recognition, automatic album creation, and iCloud sync.
• Camera: The Camera app is a built-in app that allows you to take photos and videos. The Camera app includes a variety of features, such as portrait mode, HDR mode, and Live Photos.
• Music: Music is Apple's built-in music player app that allows you to listen to music from your library, Apple Music, or other streaming services. Music also includes features such as playlists, radio stations, and lyrics.
• Podcasts: Podcasts is Apple's built-in podcast player app that allows you to listen to podcasts from a variety of sources. Podcasts also includes features such as subscribing to podcasts, creating custom playlists, and sharing podcasts with others.

11. Passing data using intent

In Android development, passing data between different components, such as activities or services, is commonly done using an Intent object. An Intent is a messaging object that allows you to communicate and transfer data between different components within an Android application. Here's how you can pass data using an Intent:

1. Sending Data:

   a. Create an Intent object: Instantiate an Intent object, specifying the source component (usually the current activity or service) and the target component (the activity or service to which you want to pass the data).

   Intent intent = new Intent(SourceActivity.this, TargetActivity.class);

   b. Add data to the Intent: You can attach data to the Intent using various methods based on the type of data you want to pass.

   For example, to pass a string value:

   intent.putExtra("key", "Hello, target activity!");

   c. Start the target component: Start the target activity or service by calling the appropriate method, such as startActivity(intent) or startService(intent).

   startActivity(intent);

2. Receiving Data:

   a. Retrieve the Intent: In the target component (activity or service), retrieve the Intent object that was used to start it.

   Intent intent = getIntent();

   b. Extract the data from the Intent: Extract the data from the Intent using the appropriate method based on the data type you expect.

   For example, to retrieve a string value:

   String data = intent.getStringExtra("key");

   Note: The key parameter used in putExtra() and getStringExtra() should match to ensure correct data retrieval.

   c. Process the data: Use the extracted data as needed within the target component.

   // Example: Display the received data in a TextView
   TextView textView = findViewById(R.id.textView);
   textView.setText(data);

12. Android Components

In Android development, Android components are fundamental building blocks that define different parts of an application's behavior and functionality. Android components are modular and can be combined to create complex and interactive applications. Here are the main types of Android components:

1. Activities: Activities represent the user interface (UI) and serve as the entry point for user interactions. Each screen in an Android application is typically implemented as an activity. Activities manage their lifecycle and handle user interactions through methods such as onCreate(), onStart(), onResume(), onPause(), onStop(), and onDestroy().
2. Services: Services are background components that perform long-running operations without a user interface. They run independently of activities and can continue to run even if the user switches to another application. Services are often used for tasks like playing music in the background, handling network requests, or performing periodic data synchronization.
3. Broadcast Receivers: Broadcast Receivers respond to system-wide or application-specific broadcast messages. They listen for and react to broadcast intents, which can be system events like device boot, network connectivity changes, or custom intents sent by other applications. Broadcast Receivers can perform actions in response to these events, such as displaying notifications or triggering other components.
4. Content Providers: Content Providers manage and expose structured sets of data to other applications. They allow sharing data across applications securely. Content Providers handle data storage, retrieval, and modification operations and enable data sharing through a standardized interface. Examples include the contacts database, media files, or user preferences.
5. Intents: Intents are messaging objects used to communicate between components. They can be used to start activities, bind to services, send and receive broadcast messages, or pass data between different parts of an application. Intents can carry data as extras and specify the desired action to be performed.

13. Activity Lifecycle

The activity lifecycle in Android refers to the series of states and callbacks that an activity goes through during its lifetime. Understanding the activity lifecycle is crucial for properly managing the behavior and resources of an activity. The lifecycle consists of several key methods that are called at different stages of the activity's existence. Here is an overview of the main stages of the activity lifecycle:

1. onCreate(): This method is called when the activity is first created. It is where you perform initialization tasks, such as inflating the layout, initializing variables, or setting up listeners. The onCreate() method receives the savedInstanceState parameter, which contains any previously saved state data.
2. onStart(): This method is called when the activity becomes visible to the user. At this point, the activity is in the foreground but not yet interactive. You can perform tasks like registering broadcast receivers or preparing UI elements in this method.
3. onResume(): onResume() is called when the activity is about to start interacting with the user. It is the point where the activity is in the foreground and receives user input. In onResume(), you typically start animations, resume sensors or location updates, or initialize resources that were paused or released in onPause().
4. onPause(): onPause() is called when the activity is partially visible or about to lose focus. It is a good place to save data that should be persisted or release resources that are no longer needed. Avoid performing time-consuming tasks in this method, as it may cause a delay in transitioning to the next activity.
5. onStop(): onStop() is called when the activity is no longer visible to the user. It occurs when another activity comes to the foreground or the activity is being destroyed. In this method, you can save any necessary persistent data or release resources that are not needed when the activity is not visible.
6. onRestart(): onRestart() is called when the activity is being restarted after being stopped. It is followed by onStart() and onResume().
7. onDestroy(): This method is called when the activity is being destroyed. It happens either because the activity finishes or the system needs to reclaim resources. Clean up any resources, unregister listeners, or perform final operations in onDestroy().

14. Broadcast Receivers:

Broadcast Receivers respond to system-wide or application-specific broadcast messages. They listen for and react to broadcast intents, which can be system events like device boot, network connectivity changes, or custom intents sent by other applications. Broadcast Receivers can perform actions in response to these events, such as displaying notifications or triggering other components.

15. Implicit intent vs Explicit intent

1. Explicit Intents: An explicit intent is used when you want to specify the target component explicitly. It explicitly identifies the specific component (activity, service, or broadcast receiver) that should handle the intent. Explicit intents are typically used within the same application to start a specific component within the app.

   Example:

   Intent explicitIntent = new Intent(SourceActivity.this, TargetActivity.class);
   startActivity(explicitIntent);

   In the example above, the explicit intent is created with the source activity (SourceActivity.this) and the target activity (TargetActivity.class). It explicitly specifies the target component by mentioning the class name.

2. Implicit Intents: An implicit intent does not specify the exact target component by class name but instead describes an action to be performed. The system then resolves the intent based on its action and the available components that can handle that action. Implicit intents are useful when you want to perform an action that can be handled by multiple components, either within your app or by external applications.

   Example:

   Intent implicitIntent = new Intent(Intent.ACTION_VIEW);
   implicitIntent.setData(Uri.parse("<https://www.example.com>"));
   startActivity(implicitIntent);

   In the example above, the implicit intent is created with the action Intent.ACTION_VIEW, which indicates that the intent is meant to view something. The intent also sets the data to be viewed as a URI (https://www.example.com). The system then resolves this intent and presents the user with a list of apps that can handle the action of viewing a webpage, and the user can choose the desired app to handle the intent.

Implicit intents can be used for a variety of actions, such as sending emails, making phone calls, sharing content, accessing device features, and more. By using implicit intents, you can allow the user to choose how they want to handle a specific action and provide flexibility in utilizing available components.

16. PhoneGap and its Advantages

PhoneGap is a cross-platform mobile app development framework that allows developers to create native apps for iOS, Android, Windows Phone, BlackBerry, and other platforms using HTML5, CSS3, and JavaScript. PhoneGap apps are built using web technologies, but they can be packaged and deployed as native apps to each platform's app store.

Advantages of PhoneGap

• Cross-platform development: PhoneGap allows developers to build a single app that can be deployed to multiple platforms, which can save time and money.
• Web technologies: PhoneGap apps are built using web technologies, which makes them easier to develop and maintain than native apps.
• Open source: PhoneGap is an open source project, which means that it is free to use and there is a large community of developers who can provide support and help with development.
• Plugins: PhoneGap has a large library of plugins that can be used to add features to apps, such as GPS, camera, and social media integration.

Disadvantages of PhoneGap

• Performance: PhoneGap apps can sometimes suffer from performance issues, especially on devices with less powerful hardware.
• Customization: PhoneGap apps can be difficult to customize to match the look and feel of a specific platform.
• Security: PhoneGap apps are not as secure as native apps, because they are built using web technologies.

Overall, PhoneGap is a good option for developers who want to build cross-platform mobile apps quickly and easily. However, it is important to be aware of the potential performance and security issues before using PhoneGap for development.

Here are some additional advantages of PhoneGap:

• Faster time to market: PhoneGap can help developers get their apps to market faster by allowing them to build a single app that can be deployed to multiple platforms.
• Reduced development costs: PhoneGap can help developers reduce development costs by eliminating the need to learn multiple programming languages and frameworks.
• Increased developer productivity: PhoneGap can help developers increase their productivity by providing a familiar development environment and a wide range of pre-built components and plugins.

17. Types of CSS

There are three types of CSS: inline, internal, and external.

• Inline CSS is the simplest type of CSS. It is used to style individual HTML elements by adding the style attribute to the element's opening tag. For example, the following code would set the font size of the h1 element to 24px:

Code snippet

<h1 style="font-size: 24px">This is a heading</h1>

• Internal CSS is used to style multiple HTML elements by placing the CSS rules in the style element of the head section of the HTML document. For example, the following code would set the font size of all h1 elements to 24px:

Code snippet

<head>
  <style>
    h1 {
      font-size: 24px;
    }
  </style>
</head>

• External CSS is used to style multiple HTML elements by creating a separate CSS file and linking to it from the head section of the HTML document. For example, the following code would link to a CSS file called styles.css:

Code snippet

<head>
  <link rel="stylesheet" href="styles.css">
</head>

The CSS file would then contain the CSS rules, such as the following code:

Code snippet

h1 {
  font-size: 24px;
}

External CSS is the most commonly used type of CSS because it allows you to keep your CSS code separate from your HTML code. This makes it easier to maintain and update your CSS code.

Here are some of the advantages and disadvantages of each type of CSS:

• Inline CSS
  • Advantages:
    • Easy to use
    • Can be used to style individual HTML elements
  • Disadvantages:
    • Can be difficult to maintain
    • Can make HTML code more difficult to read
• Internal CSS
  • Advantages:
    • Easy to use
    • Can be used to style multiple HTML elements
    • Can be kept separate from HTML code
  • Disadvantages:
    • Can make HTML code more difficult to read
• External CSS
  • Advantages:
    • Easy to maintain
    • Can be kept separate from HTML code
    • Can be reused across multiple HTML documents
  • Disadvantages:
    • Can be more difficult to set up
    • Can be slower to load than inline or internal CSS

18. Html Layout Tags

HTML layout tags are a group of HTML elements that are used to define the structure and layout of a web page. They include the following elements:

• header: The header tag defines the header of a web page. It is typically used to display the title of the page, as well as other important information such as the page's navigation menu.
• nav: The nav tag defines the navigation of a web page. It is typically used to display a list of links to other pages on the website.
• section: The section tag defines a section of a web page. It can be used to group related content together, such as articles, blog posts, or product listings.
• article: The article tag defines an independent, self-contained piece of content. It can be used to display news articles, blog posts, product descriptions, or other types of content.
• aside: The aside tag defines content that is related to the main content of a web page, but is not essential. It can be used to display sidebars, comments, or other types of supplementary content.
• footer: The footer tag defines the footer of a web page. It is typically used to display copyright information, contact information, or other legal information.

19. Html Multimedia tags

HTML multimedia tags are a group of HTML elements that are used to add multimedia content, such as audio and video, to web pages. They include the following elements:

• The <audio> tag is used to add audio content to a web page. It can be used to play back music, sound effects, or other types of audio files.
• The <video> tag is used to add video content to a web page. It can be used to play back movies, TV shows, or other types of video files.
• : The <embed> tag is used to embed multimedia content from other sources, such as Flash movies or QuickTime videos.