![]() In contrast a "while" loop runs while the control expression is true and terminates once the expression becomes false. For example, the Pascal and Lua languages have a " repeat until" loop, which continues to run until the control expression is true and then terminates. Since understand is true when the while loop gets executed, it loops through the code. It's easier to iterate over the array with for (int i 0 i < studentArray.length i++), but you can simulate that with do/while if you keep and 'manually' increment/test your own index variable. Some languages may use a different naming convention for this type of loop. While loops continue looping while the condition in brackets is true. studentArray.length will tell you how many elements are in the array. For example, a break statement would allow termination of an infinite loop. When an infinite loop is created intentionally there is usually another control structure that allows termination of the loop. It is possible and sometimes desirable for the condition to always evaluate to be true. ![]() A do-while loop provides for the action's ongoing execution until the condition is no longer true. ![]() A while loop sets the truth of a statement as a necessary condition for the code's execution. If the expression is false the loop terminates. This process is repeated as long as the expression evaluates to true. This means that the code is always executed first and then the expression or test condition is evaluated. However a while loop will test the condition before the code within the block is executed. This means the do-while loop is an exit-condition loop. This control structure can be known as a post-test loop. This repeats until the condition becomes false.ĭo while loops check the condition after the block of code is executed. If the condition is true the code within the block is executed again. ![]() First the code within the block is executed. The do while construct consists of a process symbol and a condition. $newDoc = domxml_new_doc ( '1.In most computer programming languages a do while loop is a control flow statement that executes a block of code and then either repeats the block or exits the loop depending on a given boolean condition. copying multiple 2nd level nodes from one document to another using the DOM XML extension writing the do-while seemed a bit odd without the curly braces (), but just so everyone is aware of how this is written with a do-while.Īlso, a practical example of when to use a do-while when a simple while just won't do (lol). Both while and do while are looping constructs that execute the given set of statements as long as the given condition is true. I'm guilty of writing constructs without curly braces sometimes. Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Predefined Attributes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search
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