Pseudocode

Pseudocode is an informal high-level description of the operating principle of a computer program or other algorithm.Fortran style pseudocodePascal style pseudocodeC style pseudocode:Structured Basic style pseudocode Pseudocode is an informal high-level description of the operating principle of a computer program or other algorithm. It uses the structural conventions of a normal programming language, but is intended for human reading rather than machine reading. Pseudocode typically omits details that are essential for machine understanding of the algorithm, such as variable declarations, system-specific code and some subroutines. The programming language is augmented with natural language description details, where convenient, or with compact mathematical notation. The purpose of using pseudocode is that it is easier for people to understand than conventional programming language code, and that it is an efficient and environment-independent description of the key principles of an algorithm. It is commonly used in textbooks and scientific publications that are documenting various algorithms, and also in planning of computer program development, for sketching out the structure of the program before the actual coding takes place. No standard for pseudocode syntax exists, as a program in pseudocode is not an executable program. Pseudocode resembles, but should not be confused with, skeleton programs which can be compiled without errors. Flowcharts, drakon-charts and Unified Modeling Language (UML) charts can be thought of as a graphical alternative to pseudocode, but are more spacious on paper. Languages such as HAGGIS bridge the gap between pseudocode and code written in programming languages. Textbooks and scientific publications related to computer science and numerical computation often use pseudocode in description of algorithms, so that all programmers can understand them, even if they do not all know the same programming languages. In textbooks, there is usually an accompanying introduction explaining the particular conventions in use. The level of detail of the pseudocode may in some cases approach that of formalized general-purpose languages. A programmer who needs to implement a specific algorithm, especially an unfamiliar one, will often start with a pseudocode description, and then 'translate' that description into the target programming language and modify it to interact correctly with the rest of the program. Programmers may also start a project by sketching out the code in pseudocode on paper before writing it in its actual language, as a top-down structuring approach, with a process of steps to be followed as a refinement. As the name suggests, pseudocode generally does not actually obey the syntax rules of any particular language; there is no systematic standard form, although any particular writer will generally borrow style and syntax; for example, control structures from some conventional programming language. Popular syntax sources include Fortran, Pascal, BASIC, C, C++, Java, Lisp, and ALGOL. Variable declarations are typically omitted. Function calls and blocks of code, such as code contained within a loop, are often replaced by a one-line natural language sentence.