- Tony Hoare invented the null pointer in 1960 while developing the ALGOL programming language to handle errors when accessing array elements.
- He later called the invention of the null reference his "billion dollar mistake" because it has led to many errors, vulnerabilities and system crashes over decades of use.
- Dart's new null safety features make variables non-nullable by default and require handling null values explicitly to avoid errors. Migrating code to null safety involves adding question marks to variable types, handling null values, and using tools to help with the migration.
The Decision Control Structure - C Programming. C has three major decision making instructions—the if statement, the if-else statement, and the switch statement.
Our meet-up will be focused on the basics of Flutter and introducing Flutter to existing mobile/web developers and curious developers on this exciting technology that is shaping the way mobile development will happen in the future.
Talks:
* Speaker: Arif Amirani (CTO MetroGuild Inc, Ex Directi/Veritas)
* Duration: 45 mins
* Agenda:
** Introduction to Flutter
** Comparison to Flutter/React Native/Native
** (Intro) Life Cycle of Widgets
** (Intro) State management
** Build a simple app using Flutter App in 15 mins
The Decision Control Structure - C Programming. C has three major decision making instructions—the if statement, the if-else statement, and the switch statement.
Our meet-up will be focused on the basics of Flutter and introducing Flutter to existing mobile/web developers and curious developers on this exciting technology that is shaping the way mobile development will happen in the future.
Talks:
* Speaker: Arif Amirani (CTO MetroGuild Inc, Ex Directi/Veritas)
* Duration: 45 mins
* Agenda:
** Introduction to Flutter
** Comparison to Flutter/React Native/Native
** (Intro) Life Cycle of Widgets
** (Intro) State management
** Build a simple app using Flutter App in 15 mins
JavaScript: The Good Parts Or: How A C# Developer Learned To Stop Worrying An...Doug Jones
We rarely dive into current programming languages, touting the next new framework or the new features that will be out next year. This is about JavaScript the language as it exists today, what I picked up in going from C# to JS, and what C# picked up from JS along the way as well. It is based on Douglas Crockford's seminal book "JavaScript: The Good Parts".
Introduction to Flutter - truly crossplatform, amazingly fastBartosz Kosarzycki
Intro: Flutter meaning rapid variation of electronic signal recently became Dart's framework name for mobile development. This presentation is a short introduction into a cross-platform solution covering iOS/Android. During this 45 minute period you'll learn what is flutter, where it came from and what it's for.
PHP stands for “PHP: Hypertext Preprocessor”. It is very good for creating dynamic content. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP.
Introduction to PHP: Declaring variables, data types, arrays, strings, operators, expressions, control structures, functions, Reading data from web form controls like text boxes, radio buttons, lists etc., Handling File Uploads, Connecting to database (MySQL as reference), executing simple queries, handling results, Handling sessions and cookies File Handling in PHP: File operations like opening, closing, reading, writing, appending, deleting etc. on text and binary files, listing directories
Introduction to go language programming , benchmark with another language programming nodejs , php , ruby & python . how install go . use what IDE . and rapid learnin golang
Developing Cross platform apps in flutter (Android, iOS, Web)Priyanka Tyagi
Sharing slides from my Flutter talk at SV Code Camp: https://www.siliconvalley-codecamp.com/Session/2019/developing-cross-platform-applications-using-flutter-web-android-and-ios
JavaScript: The Good Parts Or: How A C# Developer Learned To Stop Worrying An...Doug Jones
We rarely dive into current programming languages, touting the next new framework or the new features that will be out next year. This is about JavaScript the language as it exists today, what I picked up in going from C# to JS, and what C# picked up from JS along the way as well. It is based on Douglas Crockford's seminal book "JavaScript: The Good Parts".
Introduction to Flutter - truly crossplatform, amazingly fastBartosz Kosarzycki
Intro: Flutter meaning rapid variation of electronic signal recently became Dart's framework name for mobile development. This presentation is a short introduction into a cross-platform solution covering iOS/Android. During this 45 minute period you'll learn what is flutter, where it came from and what it's for.
PHP stands for “PHP: Hypertext Preprocessor”. It is very good for creating dynamic content. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP.
Introduction to PHP: Declaring variables, data types, arrays, strings, operators, expressions, control structures, functions, Reading data from web form controls like text boxes, radio buttons, lists etc., Handling File Uploads, Connecting to database (MySQL as reference), executing simple queries, handling results, Handling sessions and cookies File Handling in PHP: File operations like opening, closing, reading, writing, appending, deleting etc. on text and binary files, listing directories
Introduction to go language programming , benchmark with another language programming nodejs , php , ruby & python . how install go . use what IDE . and rapid learnin golang
Developing Cross platform apps in flutter (Android, iOS, Web)Priyanka Tyagi
Sharing slides from my Flutter talk at SV Code Camp: https://www.siliconvalley-codecamp.com/Session/2019/developing-cross-platform-applications-using-flutter-web-android-and-ios
Bhasker V Kode , (Co-Founder & CTO - Hover.in ) talking about erlang + engineering efforts at the Commercial Users of Functional Programming 2009, Edinburgh
Why Rust? by Edd Barrett (codeHarbour December 2019)Alex Cachia
For longer than I have existed, memory errors have plagued systems programming. Although many such errors are benign, sadly many end up being security vulnerabilities, or worse, exploits. In this talk, I will discuss how a security exploit is born, and how the Rust
programming language tries to prevent them.
Sinfonier: How I turned my grandmother into a data analyst - Fran J. Gomez - ...Codemotion
More than a technology, Sinfonier is the logic evolution of real time processing systems. It's the combination of a visual programming language (Yahoo Pipes), a collaborative philosophy (community) and a framework for real-time processing (Apache Storm) made available to users. During years solutions that exploit information using batch processing techs. have been growing. Now it is time to bring this philosophy to the world of real-time processing. Sinfonier was born with a clear focus on solving problems related to cybersecurity but technology supports other aspects we'll show this.
Programming is hard, but we can magnify our efforts with excellent API design. Let’s explore how, as we consider compactness, orthogonality, consistency, safety, coupling, state handling, layering, and more, illustrated with practical examples (and gruesome mistakes!) from several popular Python libraries.
PHP / MySQL applications are compatible to all operating systems, support all the popular databases, 100% remotely configurable, perfect for web programming & provide higher performance and speed.
PHP is an HTML-embedded scripting language. Much of its syntax is borrowed from C, Java and Perl with a couple of unique PHP-specific features thrown in. The goal of the language is to allow web developers to write dynamically generated pages quickly.
MySQL is a Relational Database Management System (RDBMS) that uses Structured Query Language (SQL).
PHP is the most popular scripting language for web development. It is free, open source and server-side (the code is executed on the server).
PHP third party tool and plug-in integration such as chat, forum, blog and search engine
Similar to Null safety in dart and flutter , the whole story! (20)
The current landscape of Flutter in the job market and provided insights on how to secure your dream job as a Flutter developer. Additionally, I outlined a comprehensive roadmap for mastering essential Flutter skills, as well as the soft skills crucial for career advancement.
Flutter can save your time and money, as it's now is a portable framework that allows you to compile your application for 6 different platforms and more with the same code base
Enhancing Research Orchestration Capabilities at ORNL.pdfGlobus
Cross-facility research orchestration comes with ever-changing constraints regarding the availability and suitability of various compute and data resources. In short, a flexible data and processing fabric is needed to enable the dynamic redirection of data and compute tasks throughout the lifecycle of an experiment. In this talk, we illustrate how we easily leveraged Globus services to instrument the ACE research testbed at the Oak Ridge Leadership Computing Facility with flexible data and task orchestration capabilities.
Enhancing Project Management Efficiency_ Leveraging AI Tools like ChatGPT.pdfJay Das
With the advent of artificial intelligence or AI tools, project management processes are undergoing a transformative shift. By using tools like ChatGPT, and Bard organizations can empower their leaders and managers to plan, execute, and monitor projects more effectively.
A Comprehensive Look at Generative AI in Retail App Testing.pdfkalichargn70th171
Traditional software testing methods are being challenged in retail, where customer expectations and technological advancements continually shape the landscape. Enter generative AI—a transformative subset of artificial intelligence technologies poised to revolutionize software testing.
Top Features to Include in Your Winzo Clone App for Business Growth (4).pptxrickgrimesss22
Discover the essential features to incorporate in your Winzo clone app to boost business growth, enhance user engagement, and drive revenue. Learn how to create a compelling gaming experience that stands out in the competitive market.
Enterprise Resource Planning System includes various modules that reduce any business's workload. Additionally, it organizes the workflows, which drives towards enhancing productivity. Here are a detailed explanation of the ERP modules. Going through the points will help you understand how the software is changing the work dynamics.
To know more details here: https://blogs.nyggs.com/nyggs/enterprise-resource-planning-erp-system-modules/
Gamify Your Mind; The Secret Sauce to Delivering Success, Continuously Improv...Shahin Sheidaei
Games are powerful teaching tools, fostering hands-on engagement and fun. But they require careful consideration to succeed. Join me to explore factors in running and selecting games, ensuring they serve as effective teaching tools. Learn to maintain focus on learning objectives while playing, and how to measure the ROI of gaming in education. Discover strategies for pitching gaming to leadership. This session offers insights, tips, and examples for coaches, team leads, and enterprise leaders seeking to teach from simple to complex concepts.
Cyaniclab : Software Development Agency Portfolio.pdfCyanic lab
CyanicLab, an offshore custom software development company based in Sweden,India, Finland, is your go-to partner for startup development and innovative web design solutions. Our expert team specializes in crafting cutting-edge software tailored to meet the unique needs of startups and established enterprises alike. From conceptualization to execution, we offer comprehensive services including web and mobile app development, UI/UX design, and ongoing software maintenance. Ready to elevate your business? Contact CyanicLab today and let us propel your vision to success with our top-notch IT solutions.
How Recreation Management Software Can Streamline Your Operations.pptxwottaspaceseo
Recreation management software streamlines operations by automating key tasks such as scheduling, registration, and payment processing, reducing manual workload and errors. It provides centralized management of facilities, classes, and events, ensuring efficient resource allocation and facility usage. The software offers user-friendly online portals for easy access to bookings and program information, enhancing customer experience. Real-time reporting and data analytics deliver insights into attendance and preferences, aiding in strategic decision-making. Additionally, effective communication tools keep participants and staff informed with timely updates. Overall, recreation management software enhances efficiency, improves service delivery, and boosts customer satisfaction.
OpenFOAM solver for Helmholtz equation, helmholtzFoam / helmholtzBubbleFoamtakuyayamamoto1800
In this slide, we show the simulation example and the way to compile this solver.
In this solver, the Helmholtz equation can be solved by helmholtzFoam. Also, the Helmholtz equation with uniformly dispersed bubbles can be simulated by helmholtzBubbleFoam.
Unleash Unlimited Potential with One-Time Purchase
BoxLang is more than just a language; it's a community. By choosing a Visionary License, you're not just investing in your success, you're actively contributing to the ongoing development and support of BoxLang.
Experience our free, in-depth three-part Tendenci Platform Corporate Membership Management workshop series! In Session 1 on May 14th, 2024, we began with an Introduction and Setup, mastering the configuration of your Corporate Membership Module settings to establish membership types, applications, and more. Then, on May 16th, 2024, in Session 2, we focused on binding individual members to a Corporate Membership and Corporate Reps, teaching you how to add individual members and assign Corporate Representatives to manage dues, renewals, and associated members. Finally, on May 28th, 2024, in Session 3, we covered questions and concerns, addressing any queries or issues you may have.
For more Tendenci AMS events, check out www.tendenci.com/events
Navigating the Metaverse: A Journey into Virtual Evolution"Donna Lenk
Join us for an exploration of the Metaverse's evolution, where innovation meets imagination. Discover new dimensions of virtual events, engage with thought-provoking discussions, and witness the transformative power of digital realms."
Paketo Buildpacks : la meilleure façon de construire des images OCI? DevopsDa...Anthony Dahanne
Les Buildpacks existent depuis plus de 10 ans ! D’abord, ils étaient utilisés pour détecter et construire une application avant de la déployer sur certains PaaS. Ensuite, nous avons pu créer des images Docker (OCI) avec leur dernière génération, les Cloud Native Buildpacks (CNCF en incubation). Sont-ils une bonne alternative au Dockerfile ? Que sont les buildpacks Paketo ? Quelles communautés les soutiennent et comment ?
Venez le découvrir lors de cette session ignite
Globus Compute wth IRI Workflows - GlobusWorld 2024Globus
As part of the DOE Integrated Research Infrastructure (IRI) program, NERSC at Lawrence Berkeley National Lab and ALCF at Argonne National Lab are working closely with General Atomics on accelerating the computing requirements of the DIII-D experiment. As part of the work the team is investigating ways to speedup the time to solution for many different parts of the DIII-D workflow including how they run jobs on HPC systems. One of these routes is looking at Globus Compute as a way to replace the current method for managing tasks and we describe a brief proof of concept showing how Globus Compute could help to schedule jobs and be a tool to connect compute at different facilities.
Providing Globus Services to Users of JASMIN for Environmental Data AnalysisGlobus
JASMIN is the UK’s high-performance data analysis platform for environmental science, operated by STFC on behalf of the UK Natural Environment Research Council (NERC). In addition to its role in hosting the CEDA Archive (NERC’s long-term repository for climate, atmospheric science & Earth observation data in the UK), JASMIN provides a collaborative platform to a community of around 2,000 scientists in the UK and beyond, providing nearly 400 environmental science projects with working space, compute resources and tools to facilitate their work. High-performance data transfer into and out of JASMIN has always been a key feature, with many scientists bringing model outputs from supercomputers elsewhere in the UK, to analyse against observational or other model data in the CEDA Archive. A growing number of JASMIN users are now realising the benefits of using the Globus service to provide reliable and efficient data movement and other tasks in this and other contexts. Further use cases involve long-distance (intercontinental) transfers to and from JASMIN, and collecting results from a mobile atmospheric radar system, pushing data to JASMIN via a lightweight Globus deployment. We provide details of how Globus fits into our current infrastructure, our experience of the recent migration to GCSv5.4, and of our interest in developing use of the wider ecosystem of Globus services for the benefit of our user community.
SOCRadar Research Team: Latest Activities of IntelBrokerSOCRadar
The European Union Agency for Law Enforcement Cooperation (Europol) has suffered an alleged data breach after a notorious threat actor claimed to have exfiltrated data from its systems. Infamous data leaker IntelBroker posted on the even more infamous BreachForums hacking forum, saying that Europol suffered a data breach this month.
The alleged breach affected Europol agencies CCSE, EC3, Europol Platform for Experts, Law Enforcement Forum, and SIRIUS. Infiltration of these entities can disrupt ongoing investigations and compromise sensitive intelligence shared among international law enforcement agencies.
However, this is neither the first nor the last activity of IntekBroker. We have compiled for you what happened in the last few days. To track such hacker activities on dark web sources like hacker forums, private Telegram channels, and other hidden platforms where cyber threats often originate, you can check SOCRadar’s Dark Web News.
Stay Informed on Threat Actors’ Activity on the Dark Web with SOCRadar!
Accelerate Enterprise Software Engineering with PlatformlessWSO2
Key takeaways:
Challenges of building platforms and the benefits of platformless.
Key principles of platformless, including API-first, cloud-native middleware, platform engineering, and developer experience.
How Choreo enables the platformless experience.
How key concepts like application architecture, domain-driven design, zero trust, and cell-based architecture are inherently a part of Choreo.
Demo of an end-to-end app built and deployed on Choreo.
5. Tony Hoare
Sir Charles Antony Richard Hoare born 11 January 1934)
- is a British computer scientist. He developed the sorting algorithm
quicksort in 1959–1960.[5] He also developed Hoare logic for
verifying program correctness.
https://en.wikipedia.org/wiki/Tony_Hoare /DahabDev
6. - In 1960, Hoare left the Soviet Union and began working at Elliott Brothers.
- After 9 months of programming he was asked to design a new
programming language !!
- Most software was still written in machine code.
- In the library was a 23-page booklet entitled "Report on the international
language ALGOL60"
- He used it as a basis for the new language.
- In order to implement error messages, an array had a check to verify
whether its reference was in the bounds!.
- Adding checks to arrays added space and time to the program !.
- Then he went and invented the null pointer. Or he either have to
check every reference.
https://en.wikipedia.org/wiki/Tony_Hoare
Tony Hoare in Moscow 1960
/DahabDev
11. Null
Pointer/Reference
- A null pointer is a pointer that does
not point to any memory location.
- It represents an invalid memory
location .
- when a null value is assigned to a
pointer then the pointer is considered
as null pointer.
/DahabDev
12. Null Pointer/Reference Exception (NPE)
- Invoking a method from a null object.
- Accessing or modifying a null object’s field.
- Taking the length of null, as if it were an array.
- Accessing or modifying the slots of null
object, as if it were an array.
/DahabDev
17. Tony Hoare
https://en.wikipedia.org/wiki/Tony_Hoare
I call it my billion-dollar mistake. It was the invention of the null
reference in 1965. ... This has led to innumerable errors,
vulnerabilities, and system crashes, which have probably caused
a billion dollars of pain and damage in the last forty years.
2009
/DahabDev
18. Tony Hoare
https://en.wikipedia.org/wiki/Tony_Hoare
- Null references have historically been a bad idea.
- Programming language designers should be responsible for the
errors in programs written in that language.
- If the billion dollar mistake was the null pointer, the C gets()
function is a multi-billion dollar mistake that created the
opportunity for malware and viruses to thrive (Buffer overflow)
/DahabDev
22. Dart Null Safety
Null safety is the largest
change we’ve made to Dart
since we replaced the original
unsound optional type system
with a sound static type
system in Dart 2.0.
/DahabDev
28. Dart Null safety principles
/DahabDev
Dart null safety support is based on the following three core design principles:
● Non-nullable by default. Unless you explicitly tell Dart that a variable can be null, it’s considered non-nullable.
This default was chosen after research found that non-null was by far the most common choice in APIs.
● Incrementally adoptable. You choose what to migrate to null safety, and when. You can migrate incrementally,
mixing null-safe and non-null-safe code in the same project. We provide tools to help you with the migration.
● Fully sound. Dart’s null safety is sound, which enables compiler optimizations. If the type system determines
that something isn’t null, then that thing can never be null. Once you migrate your whole project and its
dependencies to null safety, you reap the full benefits of soundness —- not only fewer bugs, but smaller
binaries and faster execution
https://dart.dev/null-safety
29. /DahabDev
- All variables are non-nullable by default
- If the variable can have the value null, add ? to its type declaration.
String? name = null;
- If you know that a non-nullable variable will be initialized to a non-null value
before it’s used, but the Dart analyzer doesn’t agree, insert late before the
variable’s type.
late String name;
Dart null safety roles
https://dart.dev/null-safety
30. /DahabDev
- When using a nullable variable or expression, be sure to handle null values. For
example, you can use an if statement, the ?? operator, or the ?. operator to
handle possible null values.
String value = name ?? ''; // '' if it's null; otherwise, the String
- If you’re sure that an expression with a nullable type isn’t null, you can add ! to
make Dart treat it as non-nullable:
String? name = 'Ahmed';
String value = name!; // `name!` is an String.
// This throws if name is null.
Dart null safety roles
https://dart.dev/null-safety
31. Dart null safety roles
/DahabDev
- Once you opt into null safety, you can’t use the member access operator (.) if the
operand might be null. Instead, you can use the null-aware version of that
operator (?.):
double? d;
print(d?.floor()); // Uses `?.` instead of `.` to invoke `floor()`.
- If you’re sure that an expression with a nullable type isn’t null, you can add ! to
make Dart treat it as non-nullable:
String? name = 'Ahmed';
String value = name!; // `name!` is an String.
// This throws if name is null.
https://dart.dev/null-safety
32. list, set, and map
/DahabDev
https://dart.dev/null-safety
33. list, set, and map
/DahabDev
https://dart.dev/null-safety
46. Migrating to null safety
/DahabDev
1. Wait for the packages that you depend on to migrate.
2. Migrate your package’s code, preferably using the interactive migration tool.
3. Statically analyze your package’s code.
4. Test to make sure your changes work.
5. If the package is already on pub.dev, publish the null-safe version as a
prerelease version.
https://dart.dev/null-safety