The usefulness of selection and repetition

Selection and Repetition Statements This chapter covers two of the most important features of the JavaScript language, selection and repetition statements. Normally, statements in a program are executed sequentially, in the order that they were written. Often it is useful to transfer control in the middle of execution to another section of code—sort of like changing trains at the terminal. The transfer might be just a couple lines of code away, as is the case with loops, or might be a different block of code all together, which is what selection statements do.

The usefulness of selection and repetition

Semantics[ edit ] Upon execution of a repetition all guards are evaluated. If all guards evaluate to false then skip is executed. Otherwise one of the guards that has value true is chosen non-deterministically and the corresponding statement is executed after which the repetition is executed again.

The usefulness of selection and repetition

Original Euclidean algorithm [ edit ] a, b: Extended Euclidean algorithm [ edit ] a, b, x, y, u, v: Applications[ edit ] Programs correct by construction[ edit ] Generalizing the observational congruence of Guarded Commands into a lattice has led to Refinement Calculus.

Asynchronous circuits[ edit ] Guarded commands are suitable for quasi-delay-insensitive circuit design because the repetition allows arbitrary relative delays for the selection of different commands.

In this application, a logic gate driving a node y in the circuit consists of two guarded commands, as follows: Unlike classical circuit evaluation models, the repetition for a set of guarded commands corresponding to an asynchronous circuit can accurately describe all possible dynamic behaviors of that circuit.

Depending on the model one is willing to live with for the electrical circuit elements, additional restrictions on the guarded commands may be necessary for a guarded-command description to be entirely satisfactory. Common restrictions include stability, non-interference, and absence of self-invalidating commands.

SPIN verifies correct operation of concurrent software applications.with Repetition • In the last section, we saw how to count combinations, where order does not matter, based on permutation counts, and we saw how to count permutations where repetitions occur. • Now, we shall consider the case where we don’t want order to matter, but we will allow.

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The selection control and repetition control structures are two of the most powerful structures in any programming language and play a critical role in increasing the power and usefulness of the program as well as providing ease to the programmer to code a wide range of functionality in its programs.

Repetition – repeating a block of code until a condition is met There are three repetition statements available in C++. The While, the Do While and the For.

The While statement is controlled by a condition. The condition is tested at the top of the loop and if the condition evaluates to. An example of combination that allows repetition is say you can choose 3 cups of ice creams for yourself from a selection of 10 ice cream flavors (chocolate, banana, mint, vanilla, hazel, peanut butter, coffee, pumpkin, caramel, strawberry).

Control structures such as selection and repetition constructs enable programmers to define variations in program flow depending upon certain conditions which may even involve repeating statements.

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Using the Online Library, the Internet, and all course materials, research arrays and control structures. The first edited volume on repetition in 20th- and 21st-century popular music, Over and Over explores the wide-ranging forms and use of repetition - from large repetitive structures to micro repetitions - in relation to both specific and large-scale issues and contexts.

The book brings together a selection of original texts by leading authors.

Control Structures