2. Software lifecycle
The life cycle of the software indicates the steps by which software
must go from conception to death.
This life cycle makes it possible to detect errors throughout the
production process and thus correct them to produce quality
software. The steps are as follows:
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3. Pre-study: This step defines the objectives of the project and defines the field
of activity. The questions to ask are: What? How much? And what?
As input, we have the needs and output we have a specification.
Analysis: This step consists of collecting and formalizing the client's needs,
defining the constraints and estimating the feasibility of these needs. The
question to ask is: What does the system do?
In input, we have the specifications, and at the exit, we have the file of analysis.
Design: This step allows to elaborate the general structure of the system and
to define each subset of the software to produce. The question to ask is: How
to do what it is asked to do?
In input, one has the file of analysis, and at the exit, one has a file of
conception.
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4. Coding: This step consists in coding or programming the functionalities
defined in the design phase.
In input, one has the file of analysis, and in exit one has programs.
Tests: This step makes it possible to test the software according to the
specifications (functional or non-functional). There are four types of tests
namely: the unit test, the integration test, the functional test, and the
validation test.
Receiving: This step allows the customer to verify the software's compliance
with the initial specifications.
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5. In input, we have a software plus a specification, and at the exit, we have a
reception report (acceptance or refusal of the deliverable)
Maintenance: This step makes it possible to take charge of the collective
actions of the system (curative and evolutionary maintenance).
At the input, we have the software, and at the exit, we have modified software.
We have seen what the key steps in the life cycle of an application are. To find
an optimal result, it is advisable to follow this approach which can undergo
improvements. Now, this article will edify you on the few models of a software
life cycle.
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6. Software life cycle models
These models define the stages of software development. At each stage,
deliverables are produced. The results are defined based on the stages and
interaction between the stages. The next step is only taken if the results are
considered satisfactory.
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7. Model in cascade
This life cycle is or angled sequentially. A phase is
Divided into several activities that can take place in
parallel. There is a break between the phases, which
means that the return on the previous phases is difficult.
Also, visualization and validation are late.
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9. Model V
The V-based model assumes that software compliance
testing against certifications must be done at the design
stage. A top-down approach before implementation is
adopted and the system is broken down as it is built. A
bottom-up approach after the implementation phase is to
be noted and the system is recomposed by testing the
parts.
The disadvantage is that validation is done at the end of
the cycle, which can be a very expensive analyst error. 9
