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In most computer programming languages, a while loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The while loop can be thought of as a repeating if statement .
Do while loops check the condition after the block of code is executed. This control structure can be known as a post-test loop. This means the do-while loop is an exit-condition loop. However a while loop will test the condition before the code within the block is executed.
However, infinite loops can sometimes be used purposely, often with an exit from the loop built into the loop implementation for every computer language, but many share the same basic structure and/or concept. The While loop and the For loop are the two most common types of conditional loops in most programming languages.
If xxx1 is omitted, we get a loop with the test at the top (a traditional while loop). If xxx2 is omitted, we get a loop with the test at the bottom, equivalent to a do while loop in many languages. If while is omitted, we get an infinite loop. The construction here can be thought of as a do loop with the while check in the middle. Hence this ...
If-then-else flow diagram A nested if–then–else flow diagram. In computer science, conditionals (that is, conditional statements, conditional expressions and conditional constructs) are programming language constructs that perform different computations or actions or return different values depending on the value of a Boolean expression, called a condition.
This approach (Boolean values are just integers) has been retained in all later versions of C. Note, that this does not mean that any integer value can be stored in a Boolean variable. C++ has a separate Boolean data type bool , but with automatic conversions from scalar and pointer values that are very similar to those of C.
In the C programming language, Duff's device is a way of manually implementing loop unrolling by interleaving two syntactic constructs of C: the do-while loop and a switch statement. Its discovery is credited to Tom Duff in November 1983, when Duff was working for Lucasfilm and used it to speed up a real-time animation program.
In 1990, The Annotated C++ Reference Manual was published. This work became the basis for the future standard. Later feature additions included templates, exceptions, namespaces, new casts, and a Boolean type. In 1998, C++98 was released, standardizing the language, and a minor update was released in 2003.