STRUCTURED PROGRAMMING CONCEPT

Structured programming has been called a revolution in programming - a systematic way to organize programs.

Structured programming can be defined as a

                        - top–down analysis for program solving

                        - modularization for program structure and organization

                        - structured code for individual modules

The four basic steps to top-down analysis are as follows:

 1. Define the complete scope of the problem to determine the basic requirement for its solution.

 2. Based on the definition of the problem, divide the problem into two or more separate parts.

 3. Carefully define the scope of each of these separate tasks and subdivide them further, if necessary, into two or more smaller tasks.

4. Repeat step 3. Every step at the lowest level describes a simple task, which cannot be broken further.

Modular programming is a program that is divided into logically independent smaller sections, which can be written separately. These sections, being separate and independent units, are called modules.

After the top-down analysis and design of the modular structure, the third and final phase of structured programming involves the use of structured code. Structured programming is a method of coding, i.e., writing a program that produces a well-organised module.

The structured program mainly consists of three types of elements:

• Selection Statements
• Sequence Statements
• Iteration Statements

The structured program consists of well structured and separated modules. The program uses single-entry and single-exit elements. 

The purpose of structured programming is to make control flow linear through a computer program so that the execution sequence follows the sequence in which the code is written.

This enhances the readability, testability, and modifiability of the program.

Types of structured programming

Structured programming can be divided into three categories, including:

1.     Procedural programming.

Defines modules as "procedures" or "functions" that are called with a set of parameters to perform a task.

2.     Object-oriented programming (OOP).

Defines a program as a set of objects or resources to which commands are sent. An object-oriented  language will define a data resource and send it to process commands. 

3.     Model-based programming.

The most common example of this is database query languages. In database programming, units of code are associated with steps in database access and update or run when those steps occur. The database and database access structure will determine the structure of the code.

The primary advantages of structured programming are:

1. It encourages top-down implementation, which improves both readability and maintainability of code.


2. It promotes code reuse, since even internal modules can be extracted and made independent,
   residents in libraries, described in directories and referenced by many other applications.


3. It's widely agreed that development time and code quality are improved through structured
   programming.