Elementary structures of structured programs
- Block: it is a command or set of commands that the program executes linearly. The sequence has a single entry point (the first line) and exit (the last line).
- Selection: it is the branching of control flow based on the outcome of a condition. When the condition is true, the 'if' block is specified, and the 'else' block is specified when it is false. The 'else' block is optional and can be left out entirely.
- Iteration: it is the repetition of a block as long as a certain condition is met. The condition is evaluated at the beginning or end of the block. When the condition returns false, the loop is terminated, and the next block is reached.
- Nesting: The aforementioned building blocks can be nested because, when encapsulated, conditions and iterations have singular entry-exit points and behave similarly to any other block.
- Subroutines: Because entire programs now have single entry-exit points, encapsulating them into subroutines allows us to call blocks with a single identifier.
Major concepts in Structured Programming
Structured programming uses three major concepts:
1. Top-down Analysis
2. Modular Programming
3. Structured Coding
Top-down Analysis
Software is always designed to perform some kind of analysis. In the world of software, this type of analysis is referred to as a problem. As a result, we must comprehend how to address the issue. The problem is broken down into small pieces with some significance in top-down analysis. Each problem is solved individually, and the steps to do so are clearly stated.
Modular Programming
While programming, the code is broken down into smaller groups of instructions. These groups are referred to as modules, subprograms, or subroutines. Modular programming is based on an understanding of top-down analysis. It discourages program jumps using 'goto statements, which render the program flow untraceable. Jumps are prohibited, and the modular format is encouraged in structured programming.
Coding Structure
Structured coding, in contrast to top-down analysis, subdivides modules into smaller units of code in the order of their execution. The control structure is used in structured programming to control the flow of the program, whereas structured coding uses control structure to organise its instructions in definable patterns.
Types of Structured Programming
Structured programming can be divided into three categories:
- Procedural programming
- Object-oriented programming (OOP)
- Model-based programming
Procedural programming
It is a programming paradigm that is based on the idea that programs are sequences of instructions that must be executed. They place a strong emphasis on dividing programs into named sets of instructions known as procedures, which are analogous to functions. A procedure can access and modify global data variables and store local data that is not accessible from outside the procedure's scope.
Fortran and ALGOL were two of the first procedural programming languages. The concepts developed in ALGOL are still very relevant and prevalent in modern programming languages.
Principles of procedural programming
→ Programs are made up of instruction sequences. There is only a thin abstraction layer between the code and the machine.
→ Procedures, which are logical blocks made up of groups of instructions, can be called from anywhere in the code.
→ A procedure can take arguments and return results to the caller. Functions can also access and modify variables in the global scope.
→ Procedural languages use block-based control flow rather than goto commands and adhere to structured programming practices.
Object-oriented programming (OOP)
It defines a program as a collection of objects or resources to which commands are sent. An object-oriented language will create a data resource and pass it to processing commands. For example, a procedural programmer may say "Print(object)," whereas an OOP programmer may say "Tell Object to Print."
Model-based programming
Database query languages are the most common example of this. Units of code in database programming are associated with steps in database access and are updated or run when those steps occur. The structure of the code will be determined by the database and database access structure. Reverse Polish Notation (RPN), a math-problem structure that lends itself to efficient solving of complex expressions, is another example of a model-based structure. Quantum computing, which is still in its early stages, is another example of model-based structured programming; the quantum computer requires a specific model to organise steps, and the language simply provides it.
Advantages of Structured Programming
- Application programs are easier to read and comprehend.
- Application programs are less likely to contain logic errors.
- Errors are more easily identified.
- It increases productivity during application program development.
- The design of application programs has been improved.
- Application programs are more easily maintained.
- Machine-Independent, mostly.
Disadvantages of Structured Programming
- It is machine-independent so converting it to machine code takes time.
- The program is dependent on variables such as data types. As a result, it must be kept up to date with the changing needs.
- The converted machine code differs from the assembly language code.
- This approach is language-dependent, so the development usually takes longer. In the case of assembly language, development takes less time because it is pre-programmed for the machine.
Frequently Asked Questions
What does structured mean in programming?
In programming, "structured" refers to the practice of organizing code into clear, logical structures using constructs like functions, loops, and conditionals. It emphasizes modularization, readability, and ease of maintenance in software development.
What is the difference between OOP and structured programming?
Object-Oriented Programming (OOP) focuses on organizing code into objects with properties and behaviors, promoting code reuse and encapsulation. Structured programming, on the other hand, relies on procedures and functions to control program flow, emphasizing modularization and procedural abstraction.
Why C is called a structured programming language?
C is a structured programming language because it divides a large problem into smaller modules called functions or procedures, each of which handles a specific responsibility. A collection of such functions constitutes the program that solves the entire problem.
Why structured programming is essential?
By using structured programming, application programs are simpler to read and comprehend. Logic errors are less likely in application programs. Errors are more easily discovered. Increased productivity while developing application programs.
Is OOP better than structured programming?
Structured Programming has less reusability and is more function dependent. Any complex program can be solved using Object-Oriented Programming. Object-Oriented Programming allows for more excellent reusability and less function dependency. There is less abstraction and flexibility. Hence, OOP is better than structured programming.
Conclusion
This article discussed structured programming. Structured programming has revolutionized software development by promoting clear, modular, and maintainable code. By organizing code into logical structures using functions, loops, and conditionals, programmers can enhance readability, reduce complexity, and facilitate collaboration.
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