Structured programming & Programming methodologies.pptx
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The document discusses structured programming and its methodologies, emphasizing the use of structured control flow constructs such as selection, iteration, and modular programming. It defines key concepts in structured programming like top-down analysis and coding structure, and categorizes structured programming into procedural, object-oriented, and model-based programming. Additionally, it outlines the principles and advantages of programming methodology, highlighting the importance of algorithms, data structures, and techniques for efficiency, reusability, and quality assurance.
Structured programming & Programming methodologies.pptx
- 1. Structured Programming & Programming Methodologies Presented by: DR Ritu Sachdeva Assistant Professor, MRIIRS
- 2. Structured Programming Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making extensive use of the structured control flow constructs of selection (if/then/else) and repetition (while and for), block structures, and subroutines
- 3. Flow of Execution The mechanisms that allow us to control the flow of execution are called control structures. Flowcharting is a method of documenting (charting) the flow (or paths) that a program would execute. The main categories of control structures: • Sequence –Simply do one instruction then the next and the next. Just do them in a given sequence or in the order listed. Most lines of code are this. • Selection – This is where you select or choose between two or more flows. The choice is decided by asking some sort of question. The answer determines the path (or which lines of code) will be executed. • Iteration – Also known as repetition, it allows some code (one to many lines) to be executed (or repeated) several times. The code might not be executed at all (repeat it zero times), executed a fixed number of times or executed indefinitely until some condition has been met. Also known as looping because the flowcharting shows the flow looping back to repeat the task. • Branching – An uncontrolled structure that allows the flow of execution to jump to a different part of the program. This category is rarely used in modular structured programming.
- 4. 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.
- 5. Top-down analysis in structured programming Top-down programming is a sequence of decomposition and partitions of functional specifications and sub- specifications until finally the level of programming language statements is reached. 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.
- 6. 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.
- 7. 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.
- 8. Types of structured programming Structured programming can be divided into three categories: • Procedural programming • Object-oriented programming (OOP) • Model-based programming
- 9. 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.
- 10. 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.
- 11. 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."
- 12. 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.
- 13. Programming Methodology Programming methodology is the process of designing, writing, testing, and maintaining computer programs. It encompasses various concepts and techniques that programmers use to develop software applications efficiently and effectively.
- 14. The key concepts of programming methodology • Algorithms: An algorithm is a step-by-step procedure for solving a problem or performing a task. Programmers use algorithms to develop the logic for their programs and ensure that they run efficiently and correctly. • Data structures: Data structures are ways of organizing and storing data in a computer. Programmers use data structures to optimize the storage and retrieval of data within their programs. • Object-oriented programming (OOP): OOP is a programming paradigm that focuses on objects, which are instances of classes that encapsulate data and behavior. OOP allows programmers to create modular, reusable, and maintainable code. • Functional programming: Functional programming is a programming paradigm that emphasizes the use of functions to perform computations. Functional programming can improve code clarity, maintainability, and reliability. • Software design patterns: Software design patterns are reusable solutions to common programming problems. They can help programmers write more efficient and maintainable code. • Code testing and debugging: Programmers use testing and debugging techniques to ensure that their code runs correctly and efficiently. This includes techniques such as unit testing, integration testing, and system testing.
- 15. Why need Programming Methodology ? • Efficiency: Programming methodology provides a systematic approach to designing and developing software applications, which can lead to more efficient and effective code. By following best practices and established techniques, programmers can optimize their code for performance, scalability, and maintainability. • Reusability: Programming methodology emphasizes the use of modular and reusable code, which can save time and resources in the long run. By developing code that can be easily adapted and reused, programmers can avoid duplicating efforts and create applications more quickly. • Quality assurance: Programming methodology includes techniques for testing and debugging code to ensure that it runs correctly and efficiently. By using these techniques, programmers can catch errors and bugs early in the development process, leading to higher-quality software applications. • Collaboration: Programming methodology provides a common language and set of tools that programmers can use to collaborate on software projects. By using established practices and techniques, programmers can communicate more effectively and work together more efficiently. • Innovation: Programming methodology provides a framework for innovation and experimentation. By using established techniques and best practices as a starting point, programmers can build on existing knowledge and create new solutions to complex problems.
- 16. 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.
- 17. 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.