Oracle Binary Code License Agreement for the Java SE Platform Products and JavaFX. Comment (computer programming) - Wikipedia, the free encyclopedia. An illustration of Javasource code with prologue comments indicated in red and inline comments in green. Program code is in blue. In computer programming, a comment is a programmer- readable annotation in the source code of a computer program. They are added with the purpose of making the source code easier to understand, and are generally ignored by compilers and interpreters. This region is specified with a start delimiter and an end delimiter. Some programming languages (such as MATLAB) allow block comments to be recursively nested inside one another, but others (such as Java) do not. For example, C++ has block comments delimited by /* and */ that can span multiple lines and line comments delimited by //. Other languages support only one type of comment. For example, Ada comments are line comments: they start with - - and continue to the end of the line. ![]() In this case it should explain the logic behind the code rather than the code itself./* loop backwards through all elements returned by the server (they should be processed chronologically)*/for(i=(num. Elements. Returned- 1); i> =0; i- -). A common logical fallacy is that code that is easy to understand does what it's supposed to do. Code description. According to this school of thought, restating the code in plain English is considered superfluous; the need to re- explain code may be a sign that it is too complex and should be rewritten, or that the naming is bad. They clarify its intent. Comments should explain, at a higher level of abstraction than the code, what you're trying to do. This is especially true of projects involving very little development time, or in bug fixing. For example: ' Second variable dim because of server errors produced when reuse form data. No' documentation available on server behavior issue, so just coding around it. System.exit(0); which can exit and if your programme involves java swing of the GUI programme you can type setDefaultCloseOperation(WindowConstants.EXIT. In such cases, comments may contain an explanation of the methodology. Such explanations may include diagrams and formal mathematical proofs. This may constitute explanation of the code, rather than a clarification of its intent; but others tasked with maintaining the code base may find such explanation crucial. This might especially be true in the case of highly specialized problem domains; or rarely used optimizations, constructs or function- calls. For example, a programmer may add a comment to explain why an insertion sort was chosen instead of a quicksort, as the former is, in theory, slower than the latter. This could be written as follows: list=. Besides, the performance really does not matter. Binary data may also be encoded in comments through a process known as binary- to- text encoding, although such practice is uncommon and typically relegated to external resource files. The following code fragment is a simple ASCII diagram depicting the process flow for a system administration script contained in a Windows Script File running under Windows Script Host. Although a section marking the code appears as a comment, the diagram itself actually appears in an XMLCDATA section, which is technically considered distinct from comments, but can serve similar purposes. This may be done to exclude certain pieces of code from the final program, or (more commonly) it can be used to find the source of an error. ![]() By systematically commenting out and running parts of the program, the source of an error can be determined, allowing it to be corrected. An example of commenting out code for exclusion purposes is below: For example, one might write: if(opt. This specific comment style is more suitable for debugging. A single slash character in front of the opening delimiter is the switch on en/disabling the block comments. Many IDEs allow quick adding or removing such comments with single menu options or key combinations. The programmer has only to mark the part of text they want to (un)comment and choose the appropriate option. It is useful with large parts of code. Guidelines, Patterns, and code for end-to-end Java applications. J2EE Application, Module, and Component Names. This includes the archive names and the display names in.Automatic documentation generation. Keeping documentation within source code comments is considered as one way to simplify the documentation process, as well as increase the chances that the documentation will be kept up to date with changes in the code. Forms of docstring are supported by Python, Lisp, Elixir, and Clojure. ![]() ![]()
Some commentators assert that source code should be written with few comments, on the basis that the source code should be self- explanatory or self- documenting. Others suggest code should be extensively commented (it is not uncommon for over 5. Such rudimentary descriptions are inconsistent with the guideline: . The occurrence of this phenomenon can be easily seen from online resources that track profanity in source code. Sections of code that are . For larger projects involving a team of developers, comment styles are either agreed upon before a project starts, or evolve as a matter of convention or need as a project grows. Usually programmers prefer styles that are consistent, non- obstructive, easy to modify, and difficult to break. For example, Variation Two might be disfavored among programmers who do not have source code editors that can automate the alignment and visual appearance of text in comments. Software consultant and technology commentator Allen Holub. If the syntax supports both line comments and block comments, one method is to use line comments only for minor comments (declarations, blocks and edits) and to use block comments to describe higher- level abstractions (functions, classes, files and modules). Sometimes projects try to enforce rules like . These kinds of rules can be counterproductive when too rigorous, but may provide a useful standard of measurement and consistency if the project participants deem it necessary. Programmers may use informal tags in comments to assist in indexing common issues. They may then be able to be searched for with common programming tools, such as the Unixgrep utility or even syntax- highlighted within text editors. These are sometimes referred to as . Further, individual programming languages sometimes provide unique variants. For a detailed review, please consult the programming language comparison article. The Ada programming language uses '- -' to indicate a comment up to the end of the line. For example: -- the air traffic controller task takes requests for takeoff and landingtasktype. Controller(My. The comment explains key terms and concepts, and includes a short signature by the programmer who authored the code./* * Check if we are over our maximum process limit, but be sure to * exclude root. This is needed to make it possible for login and * friends to set the per- user process limit to something lower * than the amount of processes root is running. These comments are caught by the Cold. Fusion engine and not printed to the browser.< !- -- This prints . Fortran 9. 0 introduced the option for inline comments. Haskell. In this all lines starting with > are interpreted as code, everything else is considered a comment. One additional requirement is that you always leave a blank line before and after the code block. In Bird- style you have to leave a blank before the code. The formatting is consistent with Sun Microsystems. Javadoc standards. The comment is designed to be read by the Javadoc processor./** * Registers the text to display in a tool tip. Multi line comments are also available via %. A comment at the beginning, called the shebang, tells the system what interpreter to use.#!/usr/bin/perlmy$s=. Properties may be specified through a hashreference like this: my $list = Pod: :List- > new(. PHPDoc is a style adapted from Javadoc and is a common standard for documenting PHP code. Power. Shell. This Python program starts with #! Software Maintenance: Concepts and Practice. Moreover, markup language is often closely integrated with programming language code, especially in the context of code generation. See e. g., Ganguli, Madhushree (2. Java for Coldfusion Developers. Upper Saddle River: Pearson Education. Computer Fundamentals and Programming in C. The Elements of Java Style. Cambridge University Press. Applied Pattern Recognition: Algorithms and Implementation in C++. Keyes, Jessica (2. Software Engineering Handbook. Web Design in a Nutshell: A Desktop Quick Reference. Sometimes the difference between a . Niederst indicates one such situation by stating: . To avoid this problem, use an XML CDATA section instead. Mac Os X for Photographers: Optimized Image Workflow for the Mac User. Learning the VI Editor. Sebastopol: O'Reilly & Associates. Practical Subversion, Second Edition. The Object Primer: Agile Model- Driven Development with UML 2. Cambridge University Press. San Francisco: No Starch Press. Intermediate Programming Principles and Techniques Using Pascal. Oracle Developer Advanced Forms & Reports. Berkeley: Osborne/Mc. Graw- Hill. Java, Java, Java: object- oriented problem solving. Prentice Hall College. Further, the appropriate level of detail is fairly well- defined: . Techniques of Program Structure and Design. University of Michigan. Non- existent comments can make it difficult to comprehend code, but comments may be detrimental if they are obsolete, redundant, incorrect or otherwise make it more difficult to comprehend the intended purpose for the source code.^Dewhurst, Stephen C (2. C++ Gotchas: Avoiding Common Problems in Coding and Design. Addison- Wesley Professional. Microsoft SQL Server 7.
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