What is the software life cycle?

Question 1: What is the life cycle of software? What are the stages of the software life cycle? Software life cycle (SDLC) is the life cycle from software generation to scrapping or stopping using. Problem definition, feasibility analysis, overall description, system design, coding, debugging and testing, acceptance and operation, maintenance and upgrading to scrapping, etc. This time-divided thinking method is an ideological principle in software engineering, that is, step by step, step by step, and each stage should be defined, worked, reviewed and documented for communication or reference, thus improving the quality of software. However, with the maturity of new object-oriented design methods and technologies, the guiding significance of software life cycle design methods is gradually decreasing.

stage

Like anything else, a software product or software system has to go through stages such as gestation, birth, growth, maturity and decline, which is generally called software life cycle. The whole software life cycle is divided into several stages, so that each stage has a clear task, and software development with large scale, complex structure and complex management becomes easy to control and manage. Generally, the software life cycle includes:

First, the definition of the problem. System analysts need to communicate with users, find out "what problems users need computers to solve" and then put forward "description of system objectives and scope" and submit it to users for review and confirmation.

Second, feasibility study. On the one hand, the goal of the system to be developed is described in clear language, on the other hand, the feasibility is analyzed from the aspects of economy, technology and law.

Third, demand analysis. Find out all the users' requirements for the software system, prepare the requirements specification and preliminary user manual, and submit them for review.

Fourth, the development stage. The development stage includes three stages:

1, design

2. Realization: Complete the coding of the source program according to the selected programming language.

3. Test

Verb (abbreviation of verb) maintenance: maintenance includes four aspects.

1, Corrective Maintenance: After the software is delivered for use, due to the incompleteness and incompleteness of development and testing, some hidden errors will inevitably be brought to the running stage, and these hidden errors will be exposed in some specific use environments.

2. Adaptive maintenance: it is the activity of modifying software to adapt to the change of environment.

3. Perfect maintenance [1]: it is a maintenance activity based on some constructive opinions put forward by users during use.

4. Preventive maintenance: It is to further improve the maintainability and reliability of the software system and lay the foundation for future improvement.

Question 2: Software life cycle Software life cycle refers to the whole process of software from definition, development, use, maintenance to scrapping, which generally includes problem definition, feasibility analysis, requirements analysis, overall design, detailed design, coding, testing and maintenance. The definition of a problem is to determine what is the problem to be solved in the development task. Through interviews with users, the system analyst finally draws a written report on the nature, engineering objectives and scale of the problem that is satisfactory to both parties. Feasibility analysis is to analyze whether the problems identified in the previous stage are feasible. System analysts should further analyze the system, determine the project scale and objectives more accurately and concretely, and demonstrate whether it is economically and technically feasible, so as to make a software plan on the basis of understanding the scope and cost of work. Requirement analysis: Even if the user's requirements are analyzed in detail, it is clear what the target system should do. All the user's requirements for the software system are expressed in the form of requirement specification. The overall design is to transform the function of the software into the required architecture, that is, to determine the module structure of the system, and give the mutual call relationship between modules, the data transmitted between modules and the functional description of each module. The detailed design is to determine the algorithm and data structure inside the module, and also to specify "how to realize this system". Coding is to select an appropriate programming language to code each template and debug the module. Testing is to make the software meet the predetermined requirements through various types of tests. Maintenance refers to the continuous inspection, correction and modification of software after it is delivered to users, so that the system can meet the needs of users permanently. The life cycle of software can also be divided into three stages, namely, planning stage, development stage and maintenance stage. Waterfall model, sometimes called V-model, is a linear sequential model, which refers to the project from requirements analysis to system testing, from beginning to end in a certain order, until it is submitted to users. It provides a structured, top-down software development method. The main work results of each stage are passed from one stage to the next, and it must be strictly examined or tested to determine whether the next stage can be started. Each stage is independent and does not overlap. Waterfall model is the basis of all software life cycle models. Prototype+Waterfall Model Prototype model itself is an iterative model, which aims to solve the problems of uncertainty, fuzziness and incompleteness in the early stage of product development. By building a prototype, developers can further determine the products they should develop, making their imagination more specific and easier for customers to understand. Prototype is only a part of the real system or model, and may not accomplish anything useful at all, usually including discard type and evolution type. Discarding refers to throwing away the prototype after it is established and analyzed, and re-analyzing and designing the whole system. Evolutionary type is a well-defined requirement, which should be preserved after the prototype is established. As the basis of the gradual increase of the system, we must pay attention to the systematicness and integrity of software design when adopting evolutionary type, and there is no shortcut in quality requirements. Therefore, it takes more time to build an evolutionary prototype than to build an abandoned prototype to describe the same function. After the prototype is established and the requirements are confirmed, the waterfall model is used to complete the project development. Incremental mode is the same as Gai Lou, and the software is built step by step. In the incremental model, software is designed, implemented, integrated and tested as a series of incremental components, and each component consists of code fragments that provide specific functions formed by various interactive modules. The incremental model does not deliver a complete product that can be run at every stage, but a subset of products that can meet the needs of customers. The whole product is divided into several components, and the developer delivers the product one by one. The advantage of this is that software development can better adapt to changes, and customers can constantly see the developed software, thus reducing the development risk. Some large-scale systems often take many years to complete, or customers are eager to realize the system. Each subsystem often adopts the mode of incremental development, which realizes the core products first, that is, the basic requirements, but many supplementary functions (some known and some unknown) will be released in the next issue. The incremental model emphasizes that every increment releases an operable product, and the construction of every increment still follows the waterfall model of design-coding-testing. Iterative model As early as the late 1950s, iterative models appeared in the software field. The earliest iterative process can be described as a "piecewise model". Iteration, including all development activities that produce product release (stable and executable product version) and all necessary activities that use the release ... >; & gt

Question 3: What is the life cycle of software? SDLC (system development life cycle) is the life cycle of software from generation to scrapping or stopping using. The old explanation is that the cycle has stages, and the problem definition, feasibility analysis, overall description, system design, coding, debugging and testing, acceptance and operation, and maintenance are upgraded to abandonment. This time-divided thinking method is an ideological principle in software engineering, that is, step by step, step by step, and each stage should be defined, worked, reviewed and documented for communication or reference, thus improving the quality of software.

With the maturity of new object-oriented design methods and technologies, the guiding significance of early software life cycle design methods gradually decreases or needs to be adjusted. [1] However, in another sense, object-oriented itself is also a software life cycle, and the traditional concept of software life cycle is still a very important knowledge base and work guide for all software engineers.

The interpretation of software life cycle should also be adjusted.

The old explanation above is not compatible with the following life cycle model, only with the waterfall life cycle model and its derivative models (such as V model and W model), but not with the life cycle model with iteration as its basic feature. The new situation is to add iteration to the stages, which are as follows: there are stages in the software life cycle, such as problem definition, feasibility analysis, overall description, system design, coding, debugging and testing, acceptance and operation, maintenance and upgrading to abandonment, and there are also iterative stages that combine the activities of the above stages, that is, iteration is the stage of life cycle.

Question 4: What is the life cycle of an application? Like anything else, a software product or software system has to go through stages such as gestation, birth, growth, maturity and decline, which is generally called software life cycle. The whole software life cycle is divided into several stages, so that each stage has a clear task, and the software development with large scale, complex structure and complex management becomes easy to control.

Question 5: What is the life cycle model of software? What are its main models? A: The software life cycle model is a model that describes how various activities are executed in the process of software development. There are waterfall model, prototype model, incremental model, spiral model, fountain model, knowledge model and transformation model.

Question 6: What is the difference between software life cycle and software testing life cycle? The differences are as follows:

Software life cycle refers to the whole cycle of software from production to scrapping, including seven stages: feasibility analysis, project planning, requirements analysis, overall design and detailed design, coding, debugging and maintenance.

Software testing life cycle refers to the whole testing process from the formulation of test project plan to BUG submission, including five stages: software project test plan, test requirement analysis, test case design, test case execution and BUG submission.

In addition, the connections are as follows:

Parallelism of software testing life cycle and software life cycle exist in all stages of software life cycle.

Question 7: The software life cycle is usually called three periods and eight stages. What are the eight stages of these three periods? The 30-minute software life cycle includes eight stages. In order to make the task of each period more clear, it can be divided into the following three periods: software definition period, software development period and software maintenance period.

Question 8: What is software lifecycle management to solve management problems? Only with the software life cycle model can managers determine what to do at that stage, and manage different projects according to different life cycle models to improve software quality and efficiency. In a word, the project chooses the corresponding life cycle model in order to better manage the project development.

Question 9: What is the software life cycle? And what are the main tasks of each stage? 1. Software development process-the basic task of each stage of life cycle

1) Software definition

(1) problem definition

(2) Feasibility study

(3) Requirements analysis-What tasks must the system complete?

2) Software development

(1) Overall design DD In a word, how to realize the system?

(2) Detailed design

(3) Coding and unit testing

(4) Comprehensive test

3) Software maintenance

(1) Corrective maintenance

(2) Adaptive maintenance

(3) Perfect maintenance

(4) Preventive maintenance

2. Training topics:

Enterprise customer management information system

3. System requirements:

Application background:

Enterprise customer management is an important part of company management. With the increasingly fierce market competition, if we can have more customers, it will be the ultimate factor for the long-term survival of enterprises.

The job of maintaining customer information is to save the basic information of enterprise customers, such as company name, address, main industry, contact name and address, etc. And maintain a dynamic information to ensure the consistency of information. In order to protect customer information as much as possible, the system can delete company information, but not personal information, thus maintaining the most customers. If the work of maintaining customer information is done only by manpower, there will be many problems in the middle. The first is a waste of manpower. When the number of customers in an enterprise reaches a level, it is impossible to maintain huge customer information by manpower alone. If there is an automatic and systematic management system to maintain enterprise customer information, it will be able to provide great help to enterprises.

The object of enterprise management information system is enterprises and institutions managed by enterprises.

Customer management system provides information preservation, information modification and information consultation services for enterprises and institutions.

The traditional data marking management of paper materials is no longer suitable for the development of contemporary enterprises. Realizing the systematization, standardization and automation of customer management will become the first choice for contemporary companies to manage customer information.

The system provides general customer information that needs to be maintained. The system flexibly uses tables to classify all kinds of information, forming an enterprise customer management system, which is convenient for query, reading, modification, communication and reuse.

Functional requirements:

The purpose of this system is to help enterprises improve work efficiency, ensure the accuracy and real-time of customer information, and realize the systematization, standardization and automation of enterprise customer information management. According to this purpose and task, the main functions of the system are:

1. System management part:

A) After logging in as an administrator, you can add other users.

B) No matter what kind of user logs in, the password can be changed.

2. Personal information management part:

A) Add personal information: including name, gender, age, birthday, company, position, country, city, mailing address, telephone number, fax number, email address and other information.

B) Modify personal information: modify all personal information.

C) Inquiring about personal information: inquiring about personal information by company.

3. Enterprise information management part:

A) Add enterprise information: including company name, country, main business areas, cooperation areas with the company, address, telephone number, fax number and other information.

B) Modify enterprise information: modify various information of the company.

C) Inquiring about enterprise information: inquiring about enterprise information according to business fields.

D) Delete enterprise information: delete non-customer enterprise information.

4. Data management

A) export customer information in Word or Excel format.

B) print customer information

Performance requirements:

Under reasonable circumstances, it must be realized.

The program should be able to respond to unreasonable situations.

All controls used in the program are abbreviated. Refer to the textbook for details. For example, mand 1, as a button to add information, is renamed as cmdAdd, so that you can know what control it is and what function it has when you see the name of the object.

Need a menu system

For the main form where the menu is located, an MDI form is required.

If you are interested, you can try to add a toolbar or a right-click menu.

4. Data control

5.ADO control

6.ADO object

Use of 7.7. MSFlexGrid control ... >; & gt