What is the software development process?

1. Relevant system analysts have a preliminary understanding of users' needs, and then list the main functional modules of the system that need to be developed with relevant tools and software, and what are the secondary functional modules of each main functional module. For some requirements, when the relevant interfaces are clear, this step can initially define a small number of interfaces.

2. The system analyst deeply understands and analyzes the requirements, and then according to his own experience and requirements, uses WORD or related tools to make the functional requirements document of the document system. This document will clearly list the general main functional modules of the system, which secondary functional modules are included in the main functional modules, and also list the related interfaces and interface functions.

3. The system analyst reconfirms the requirements to the user.

master design

First, developers need to design software systems, that is, system design. Summary design needs to consider the design of software system, including basic processing flow, organizational structure, module division, function allocation, interface design, operation design, data structure design and error handling design, so as to provide basis for detailed design of software. [2]

Detail design

On the basis of overall design, developers need to design the software system in detail. In the detailed design, it is necessary to describe the main algorithms, data structures, hierarchical structure of classes and call relationships involved in the implementation of specific modules, and explain the design considerations of each program (each module or subroutine) at all levels of the software system for coding and testing. You should ensure that the requirements of the software are completely distributed throughout the software. The detailed design should be detailed enough to be coded according to the detailed design report.

encode

In the software coding stage, according to the design requirements of data structure, algorithm analysis and module realization in the detailed design report of the software system, developers began to write specific programs to realize the functions of each module, so as to meet the requirements of the target system in terms of function, performance and interface. In the standardized R&D process, the coding work in the whole project process will not exceed 1/2 at most, usually 1/3. As the saying goes, if the design process is completed well, the coding efficiency will be greatly improved, and the progress coordination and cooperation between different modules is the most important thing in coding. Perhaps a small module problem may affect the overall progress, so many programmers are forced to stop working and wait. Communication and emergency plan are very important when coding. For programmers, bugs will always exist, and you must face this problem forever!

test

Test the written system. Give it to the user, and the user will confirm each function one by one after use. There are many kinds of software testing: according to the tester, it can be divided into internal testing and external testing; According to the test scope, it can be divided into module test and overall debugging; According to the test conditions, it can be divided into normal operation test and abnormal situation test; According to the input range of the test, it can be divided into full coverage test and sampling test. The above is easy to understand, so I won't explain it. In short, testing is also a very important step in project development. For a large-scale software, it is normal for an external test to take 3 months to 1 year, because there will always be unpredictable problems. After testing, acceptance and final help documents are completed, the whole project will come to an end. Of course, there will be upgrades, maintenance and so on in the future. As long as you don't want to cheat money with one hammer, you must keep track of the running state of the software and continue to repair and upgrade it until the software is completely eliminated.

Software delivery

After the software test proves that the software meets the requirements, the software developer shall submit the developed target installation program, data dictionary of database, user installation manual, user guide, demand report, design report, test report and other products agreed by both parties to the user.

The user installation manual should introduce in detail the requirements of the installation software for the running environment, the definition and content of the installation software, the specific installation steps on the client, server and middleware, and the system configuration after installation.

The user's guide should include the use process, operation steps, corresponding business introduction, special tips and precautions of various functions of the software, and examples should be given when necessary.

Step 1: Business negotiation. Understand the customer's needs first, make a preliminary plan according to the customer's consultation, and give a quotation after the customer verifies that there is no problem. The customer confirms the previous contract and pays the intention money. Step 2: Project planning. The product manager combed the product planning and design, prototype design and functional logic, and the project was officially launched. Step 3: UI design Part 4: Program development Step 5: Testing Step 6: On-line Final Step: Post-maintenance.

analyse

Software requirements analysis is to answer the question of what to do. It is a process of removing the rough and selecting the fine, removing the false and retaining the true, correctly understanding the user's requirements, and then expressing them in software engineering development language (formal functional specification, that is, requirement specification). The basic task of this stage is to determine the problems to be solved with the users, establish the logical model of the software, write the requirements specification document, and finally get the approval of the users. The main methods of requirement analysis are structured method, data flow chart and data dictionary. The work in this stage is to design and establish the corresponding software system architecture according to the requirements of the requirement specification, decompose the whole system into several subsystems or modules, define the interface relationship between subsystems or modules, define the specific design of each subsystem, write the software outline design and detailed design specification, database or data structure design specification, and assemble the test plan.

design

Software design can be divided into two stages: overall design and detailed design. In fact, the main task of software design is to decompose software into modules, which refer to data and program descriptions that can realize a certain function and program units that can execute programs. It can be a function, a process, a subroutine, an independent program and data with program description, or it can be a functional unit that can be combined, decomposed and replaced. Module, and then module design. Summary design is structural design, and its main goal is to give the module structure of software and express it with software structure diagram. The primary task of detailed design is to design the program flow, algorithm and data structure of the module, and the secondary task is to design the database, common methods or structured programming methods.

encode

Software coding refers to converting a software design into a program acceptable to the computer, that is, writing a list of source programs in a programming language. A full understanding of software development language, tool characteristics and programming style is helpful to choose development tools and ensure the development quality of software products.

At present, except for special occasions, the high-level language of the 1980s is rarely used in software development, and it is replaced by the object-oriented development language. Moreover, the object-oriented development language and development environment are mostly integrated, which greatly improves the development speed.

test

The purpose of software testing is to find as many errors as possible at a small cost. The key to achieve this goal is to design a set of excellent test cases (test data and expected output results constitute test cases). How to design a set of excellent test cases depends on the understanding of test methods. Different test methods have different test case design methods. Two commonly used testing methods are white-box method, which tests the source program and finds programming errors, structural errors and data errors according to the internal logical structure of the program. Structural errors include logic, data flow, initialization and other errors. The key of use case design is to cover as many internal program logic results as possible with fewer use cases. White box method and black box method are based on the description of software function or software behavior, looking for interface, function and structure errors of software. Interface errors include internal/external interfaces, resource management, integration and system errors. The key of black-box use case design is to cover the output and input interfaces of the module with fewer use cases. Black box method.

maintain

Maintenance refers to some software engineering activities of software products after software development (analysis, design, coding and testing) is completed and delivered for use. That is, according to the operation of the software, the software is modified appropriately to meet the new requirements and the errors found in the operation are corrected. Compile software problem report and software modification report.

If the development stage of a medium-sized software takes one to two years, it may take five to ten years to run or work after it is put into use. Then its maintenance phase is also during the five to ten years of operation. During this period, people almost need to solve all kinds of problems encountered in the development stage, but also need to solve some problems unique to the maintenance work itself. Doing a good job in software maintenance can not only remove obstacles and make the software work normally, but also expand functions, improve performance and bring obvious economic benefits to users. Unfortunately, however, the emphasis on software maintenance is often far less than that on software development. In fact, the workload and cost of software maintenance is much larger than that of software development.

In the actual development process, software development is not from the first step to the last step, but at any stage, there are usually one or several steps back before entering the next stage. Problems in the testing process may need to modify the design, and users may put forward some requirements to modify the requirements specification.

Software development is generally divided into five stages:

1. Definition and planning of the problem

2. Demand analysis

3. Software design

4. Program coding

5. Software testing

6. Software maintenance

Software development is generally divided into five stages:

1. Definition and planning of the problem

This stage is the discussion of software development and requirements, mainly to determine the development goal and feasibility of software.

2. Demand analysis

Under the condition of determining the feasibility of software development, the requirements of each function that the software needs to realize are analyzed in detail. The requirement analysis stage is a very important stage. If this stage is done well, it will lay a good foundation for the development of the whole software project. The only constant is the change itself. Similarly, software requirements are constantly changing and deepening in the software development process. Therefore, we must customize the demand change plan to deal with this change, so as to ensure the normal progress of the whole project.

3. Software design

At this stage, I occasionally design the whole software system according to the results of demand analysis, such as system framework design and database design. Software design is generally divided into overall design and detailed design. The improved software design will lay a good foundation for software programming.

4. Program coding

This stage is to transform the result of software design into computer executable program code. It is necessary to formulate a unified and standard writing specification in program coding. Ensure the readability and maintainability of the program. Improve the running efficiency of the program.

5. Software testing

After the software design is completed, it should be strictly tested, and once the problems existing in the whole software design process are found, it should be corrected. The whole testing stage is divided into three stages: unit testing, assembly testing and system testing. Test methods mainly include white box test and black box test.