C++ *

A graph is a kind of data structure that includes a set of vertices and edges. Graph traversing means a visit to each vertex of the graph precisely. The graph traversing is used to determine the order in which vertices are being visited throughout the search process. A graph traversing searches for the edges that will be used in the search operation without establishing loops. This means that using graph traversal, we will go to all the vertices of the graph without going into a looping path.

There are two kinds of graph traversal methods.

Stack

Stack is a linear data structure. In stack, data access is limited. It follows the rule of insertion and deletion of data. Stack is a collection of only similar data types. Elements in the stack are arranged sequentially. It follows the LIFO principle which is the last-in and first-out rule.

Example

To understand this concept, let us take an example of arranging coins. If we start placing coins one after the other in such a way that the first coin will be placed first at the bottom and the next coin will come on above the first coin and so on. Now if we want to remove coins, then the topmost coin which is the third coin will be removed first. So in this way, the last coin will be removed first according to the LIFO principle.

"How much longer are you going to build it?" - a phrase that every developer has uttered at least once in the middle of the night. Yes, a build can be long and there is no escaping it. One does not simply redistribute the whole thing among 100+ cores, instead of some pathetic 8-12 ones. Or is it possible?

Somehow, it so happens that we write about our diagnostics, but barely touch upon the subject of how we enhance the analyzer's internal mechanics. So, for a change, today we'll talk about a new useful upgrade for our data flow analysis.

At the very beginning of this year, Apple released the source code for macOS – Big Sur. It includes XNU, the kernel of the macOS operating system. A few years ago, PVS-Studio has already checked the kernel source code. It coincided with the analyzer release on macOS. It's been a while since then. The new kernel source code has been released. A second check? Why not?

Most influential programmers say that code must be self-documenting. They find comments useful only when working with something uncommon. Our team shares this opinion. Recently we came across a code snippet that perfectly proves it.

Users sometimes ask how new diagnostics appear in the PVS-Studio static analyzer. We answer that we draw inspiration from a variety of sources: books, coding standards, our own mistakes, our users' emails, and others. Recently we came up with an interesting idea of a new diagnostic. Today we decided to tell the story of how it happened.

Having only programming background, it is impossible to develop software in some areas. Take the difficulties of medical software development as an example. The same is with music software, which will be discussed in this article. Here you need an advice of subject matter experts. However, it's more expensive for software development. That is why developers sometimes save on code quality. The example of the MuseScore project check, described in the article, will show the importance of code quality expertise. Hopefully, programming and musical humor will brighten up the technical text.

In our articles, we regularly repeat an important idea: a static analyzer should be used regularly. This helps detect and cheaply fix many errors at the earliest stage. It looks nice in theory. As we know, actions still speak louder than words. Let's look at some recent bugs in new code of the Blender project.

Recently we found out that the new version of the fheroes2 project was released. In our company there are many fans of Heroes of Might and Magic game series. So, we couldn't pass it up and checked the project by PVS-Studio.

rotor is a non-intrusive event loop friendly C++ actor micro framework with hierarchical supervising, similar to its elder brothers like caf and sobjectizer. There is a bulk of important changes since the last release announcement v0.09

As Intel Threading Building Blocks (TBB) is being refreshed using new C++ standard, deprecating tbb::task interface, the need for high-level tasking interface becomes more obvious. In this article, I’m proposing yet another way of defining what a high-level parallel task programming model can look like in modern C++. I created it in 2014 and it was my last contribution to TBB project as its core developer after 9 wonderful years of working there. However, this proposal has not been used in production yet, so a new discussion might help it to be adopted.

An essential part of any modern static code analyzer is data flow analysis. However, from an outside perspective, the use of data flow analysis and its benefit is unclear. Some people still consider static analysis a tool searching for something in code according to a certain pattern. Thus, we occasionally write blog posts to show how this or that technology, used in the PVS-Studio analyzer, helps to identify another interesting error. Today, we have such an article about the bug found in the Base64, one of the encoding standard implementations of binary data.

The recent Qt 6 release compelled us to recheck the framework with PVS-Studio. In this article, we reviewed various interesting errors we found, for example, those related to processing dates. The errors we discovered prove that developers can greatly benefit from regularly checking their projects with tools like PVS-Studio.

Static code analysis is a crucial component of all modern projects. Its proper application is even more important. We decided to set up a regular check of some open source projects to see the effect of the analyzer's frequent running. We use the PVS-Studio analyzer to check projects. As for viewing the outcome, the choice fell on SonarQube. As a result, our subscribers will learn about new interesting bugs in the newly written code. We hope you'll have fun.

Let's say you use GitHub, write code, and do other fun stuff. You also use a static analyzer to enhance your work quality and optimize the timing. Once you come up with an idea - why not view the errors that the analyzer gave right in GitHub? Yeah, and also it would be great if it looked nice. So, what should you do? The answer is very simple. SARIF is right for you. This article will cover what SARIF is and how to set it up. Enjoy the reading!

There is an open project COVID-19 CovidSim Model, written in C++. There is also a PVS-Studio static code analyzer that detects errors very well. One day they met. Embrace the fragility of mathematical modeling algorithms and why you need to make every effort to enhance the code quality.

One of our readers recommended paying heed to the Espressif IoT Development Framework. He found an error in the project code and asked if the PVS-Studio static analyzer could find it. The analyzer can't detect this specific error so far, but it managed to spot many others. Based on this story and the errors found, we decided to write a classic article about checking an open source project. Enjoy exploring what IoT devices can do to shoot you in the foot.

This part covers the use of typemaps, complex & weird cases, and debugging suggestions. This part requires an understanding of Part 1 - usage of SWIG in simple cases.

This is a practical Android-first guide, with Android Studio project you can play with.

SWIG is a tool for generating cross-language interfaces - it provides interoperability of C++ and other languages (C++ and Java in our case). SWIG just simplifies and automizes cross-language interaction; otherwise, you may end up with thousands of lines of handwritten JNI code - but SWIG covers this for you.

This guide is for newbies (Part 1) and for those who experienced in SWIG (part 2). I'm starting from basic setup and usage and ending with complex & weird cases encountered in development. The latter cases are not so complex, rather usual for modern languages, which SWIG doesn't support yet (as lambdas).

This guide is practical. In opposition to overcomplicated huge-volume SWIG documentation, this guide is showing the cases practically. The bits developed by myself while working on the different projects or taken from StackOverflow. This guide allows you to quick-start an Android Studio project and giving practical examples of using SWIG. The link to the Android Studio project is here.

This guide is Android-first. The goal was to make it simple to onboard for Android developers. There are many articles about SWIG, but they are mainly for desktop Java applications, and it is quite an overhead to just try them on Android to check if the solution for the particular problem is working. While this guide includes an Android Studio project, with which you can play around instantly. Of course, all the information given here applies to any Java application.

Warning! I should warn you, that nowadays cross-platform development offers powerful tools. If you are developing a new application it is much more cost-efficient in practice to use ReactNative, Flutter of Kotlin-Native than the SWIG. While SWIG is more suitable to connect the C++ library or existing C++ application core.