STRUCTURED PROGRAMMING

Structured programming is a programming theory is to build programs understandable,  it is especially useful when you need to make corrections or changes after the completion  of a program or application. By using structured programming is much easier to understand  the coding of the program, which will have been done in different sections. It is based on a software development methodology called successive refinement: an  operation is proposed as a whole is divided into segments simpler or less complex, once  completed all segments of the program proceeds to unify the applications made by the group  of programmers. If you have used properly structured programming, this integration should be  simple and have no problems integrating it, and to present a problem, will be quickly detectable  for correction. The graphic representation of structured programming is done through flow charts, which  represents the program with inputs, processes and outputs. Structured programming processes proposed structures segregate as simple as possible, which are known as sequence, selection and interaction, which are available in all modern programming languages ​​in the form of imperative sentences by combining simple schemes can get to build systems large and complex but easy to understand. Structured programming is a disciplined approach to writing programs that are clear, proven  to be correct and easy to modify. Structured programming is divided into modules and programs are based on the development of programs ranging from general to particular, ie, the element set is said of a particularly specific. To solve a particular problem, start by considering the functions that must meet the overall  program and then dismembering these functions is smaller subfunctions until the last one  or more particular case and no longer can be subdivided into cases smallest. Once the program has already been dismembered in the general to the particular, is beginning to  program these small functions, private or modules, in this way, we can always build new modules or units by inserting the name of the module and developing appropriate part. modification of the modules is easy and can be referenced as many times as needed, thereby  saving time in the program, a program has a structured design if it meets the following two conditions: The structure theorem. Is properly documented The structure theorem states that "a program meets the structure theorem if and only (or) if you  own and contains only three basic control structures" that are sequential, alternative and  repetitive, a program is proper if and only if it satisfies: having a single point of entry and one exit point, and in two control points of the program exists at least one way. Structured programming is a style with which he seeks to develop programs that the  programmer simple and easy to understand, structured programming makes use of three  basic structures of control are: Sequential Structure, Structure and Structure Selective repetitive  (or iterative) Structured programming is based a fundamental theorem, which states that any program, no matter what kind of jobs that can be produced using only the three basic structures. DEFINITION OF THE BASIC STRUCTURES 3 1. Sequential structure: Indicates that the program instructions are executed one after the other in the same order in which they appear in the program. Is plotted as a box after another, each with a single input and single output. Boxes A and B can be defined to run from a single instruction to a module or complete program, provided they are also appropriate programs. 3. Repetitive structure (Iterative): Also called the structure to do - while - that corresponds to the repeated execution of an instruction while a certain condition is met. The flow diagram for this structure is as follows: Here the block A is executed repeatedly while the condition is fulfilled or C is true. It also has one input and one output, same as can be any basic structure or set of structures. 2. Selective Structure: Also known as the structure if true - false, poses the choice between two alternatives based on the outcome of the evaluation of a condition, is equivalent to the IF of all programming languages ​​and is graphically represented as follows : In the above flow diagram, C is a condition that is evaluated, A is the action that is executed when the evaluation of this condition is true and B is the action executed when the result of the evaluation indicates false. The structure also has one entrance and one exit, and the functions A and B can also be any basic structure or set of structures. ADVANTAGES OF STRUCTURED PROGRAMMING In structured programming, develop computer programs remains a work that demands effort, creativity, skill and care.However, with this new style we obtain the following advantages: 1. Programs are easier to understand, a structured program can be read in sequence, from top  to bottom without having to be jumping from one site to another logic, which is typical of other  styles of programming. 2. It achieves a reduction of effort in testing, monitoring or debug faults (debugging) is provided  due to the logic more visible, so that errors can be detected and corrected more easily. 3. Programs are created easier and faster. DIFFERENCES structured programming with other programming Although structured programming led to improvements in sequential programming  technique, modern methods of software design including object-oriented  improvements among which are the use of design patterns, design by contract,  and modeling languages, the main differences between structured programming  and object oriented are: Object-oriented programming is more modern, is an evolution of structured  programming that captures the design of a family of languages ​​concepts that previously existed with some new. Object-oriented programming languages ​​is based on syntactic and semantic  supporting the link between abstract data types and operations. The object-oriented programming features in runtime mechanisms such as  polymorphism and sending messages between objects. Erroneously ascribed to classical structured programming as if they were certain  problems inherent in it, those problems were becoming more severe and before the  various object-oriented programming authors found solutions to apply strict working  methods. From this period are the concepts of cohesion and coupling of these  problems are the following: Abnormal mental model. Our image of the world rests in people, to which we attach nouns, while the classical programming is based on behavior, usually represented  by verbs. It is difficult to modify and extend the programs, as there are often shared by            several sub-data, which introduce hidden interactions between them. It is difficult to maintain the programs. Almost all large computer systems have              hidden errors that do not come to light until after many hours of operation. It is difficult to reuse programs. It is virtually impossible to take on a new                application subroutines that were designed for another. It is complex coordination and organization among developers creating                 applications for medium and large. In pure object-oriented programming should not be used subroutine calls, messages  only, therefore, sometimes called no call schedule, like structured programming is also  called programming without goto, however, not all oriented languages to prohibit the call instruction objects, enabling hybrid programming, imperative, object-oriented at  a time.