XOR is a bitwise operator, and it stands for \"exclusive or.\" It performs logical operation. If input bits are the same, then the output will be false(0) else true(1).
\nXOR table:
\n| X | \nY | \nX^Y | \n
|---|---|---|
| 0 | \n0 | \n0 | \n
| 0 | \n1 | \n1 | \n
| 1 | \n0 | \n1 | \n
| 1 | \n1 | \n0 | \n
Example: 4^3 = 7
In binary: \n\t 0100\n\t ^ 0011\n\t ------\n Result: 0111 => (7)Let's understand with an example -4^-2 = 2\nIn the above example, we can see -4^-2output will be 2\nbut the question arises how? Because if we represent both inputs in the binary form, then we do XOR of bits, then the output will be 0000 0110 and in decimal, it will be 6 but as we know output should be 2.
1000 0100 (-4)\n^ 1000 0010 (-2)\n------------------\n 0000 0110 => (6) // incorrect output\n\nNote: Here, the leftmost bit position is reserved for the sign of the\nvalue (positive or negative) and doesn't contribute towards the value of the number.
\n
Let's understand how the XOR operation works with negative numbers.
\nFirst, the XOR operation is to XOR each bit (the same is 0, the difference is 1), but you need to convert the number into a complement first.
\nThe complement of the negative number is reversed for each bit and then incremented by 1 (the highest is kept at 1)
\n// Lets take -4\nIn binary: \t\t\t1000 0100\nReverse: \t\t\t1111 1011\ncomplement (Increment by 1): \t1111 1100// Now -2\nIn binary: \t\t\t1000 0010\nReverse: \t\t\t1111 1101\ncomplement (Increment by 1): \t1111 1110
\nFinal result:
\ncomplement of -4 : 1111 1100\ncomplement of -2 : 1111 1110\n -----------\nResult: 0000 0010 \t=> 2Here, the MSB bit of result will denote the sign, and the rest of the bits will denote the value of the final result.\nXOR sign table could be useful to understand the sign of result:
\n| X | \nY | \nX^Y | \n
|---|---|---|
| + | \n+ | \n+ | \n
| + | \n- | \n- | \n
| - | \n+ | \n- | \n
| - | \n- | \n+ | \n
The above approach will work with negative inputs, but if we have positive and negative, then?
\nLet's performs -5 ^ 2\nFollow the same above approach to get a complement code of -5.
complement of -5 : 1111 1011\n// Note: complement of a positive number is itself\ncomplement of 2 : 0000 0010 \ncomplement result: 1111 1001\n\nNow, complement result -1 : 1111 1000\n -----------\nFinal result(inverse code): 1000 0111 => -7Swap two number without the third variable\nExample:
\nfunction swapWithXOR (a, b) {\n a = a^b;\n b = a^b;\n a=a^b;\n console.log("result => a: " + a + ", b: " + b)\n}\n\nswapWithXOR(4, 1); // result => a: 1, b: 4Have you ever heard of SonarQube? Would you like to know What it is? And how to use it? And its benefits to the production phase of software development. Then you are at the right place; in this tutorial of SonarQube, I will give you a walkthrough of every aspect of SonarQube.
\nLet's dive in!!!
\nSonarQube is an open-source platform developed by SonarSource for continuous inspection of code quality. Sonar does static code analysis, which provides a detailed report of bugs, code smells, vulnerabilities, code duplications.
\nIt supports 25+ major programming languages through built-in rulesets and can also be extended with various plugins.
\nDevelopers working with hard deadlines to deliver the required functionality to the customer. It is so important for developers that many times they compromise with the code quality, potential bugs, code duplications, and bad distribution of complexity.
\nAdditionally, they tend to leave unused variables, methods, etc. In this scenario, the code would work in the desired way.
\nDo you think this is a proper way to deliver functionality?
\nThe answer is NO.
\nTo avoid these issues in code, developers should always follow the good coding practice, but sometimes it is not possible to follow the rules and maintain the good quality as there may be many reasons.
\nIn order to achieve continuous code integration and deployment, developers need a tool that not only works once to check and tell them the problems in the code but also to track and control the code to check continuous code quality. To satisfy all these requirements, here comes SonarQube in the picture.
\nThis section will explain the steps or procedures to configure the sonarqube plugin for all the major programming languages.
\nThe only prerequisite for running SonarQube is to have Java (Oracle JRE 11 or OpenJDK 11) installed on your machine. [details]
\nSet the PATH system variable: How do I set or change the PATH system variable?
\n\n\nNote: In order to analyze JavaScript code, you need to have Node.js >= 8 installed on the machine running the scan. If a standard node is not available, you have to set the property
\nsonar.nodejs.executableto an absolute path to Node.js executable. [details]
To start the sonar server open cmd or terminal and set sonarqube bin folder path and choose the platform and run the following command. Examples :
\n#For Windows(cmd):\nC:\\sonarqube\\bin\\windows-x86-64>StartSonar.bat\n#For other OS (terminal): \nC:\\sonarqube\\bin\\[OS]>sonar.shOnce the sonar server up successfully, then Log in to http://localhost:9000 with System Administrator credentials (login=admin, password=admin).
http://localhost:9000/account/security page).Now copy the displaying command and Go to your project path and Run the copied command. It looks like below:
\nsonar-scanner.bat -D"sonar.projectKey=rtetre" -D"sonar.sources=."-D"sonar.host.url=http://localhost:9000" -D"sonar.login=e932dxxxxx9a8e5c7903xxxxxx96928xxxxxxx"After the analysis is done, you can either browse the provided link to see the sonar report directly [Ex.: http://localhost:9000/dashboard?id=] or go to the project section to see the newly generated sonar report of your project.
If you want to exclude some files from analysis(like test files), then go to the administration section and navigate to the General setting, select the programming language used, and set a list of file path patterns to be excluded from the analysis.
\nNow re-run the analysis command given above for an updated sonar report.
\nThe goal of SonarQube is to empower developers first and to grow an open community around the quality and security of code. I hope with this quick tutorial of sonarqube you have the basic idea of the functionalities, and If you believe so, drop a comment and show your support.
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