Explain sdlc?

There are 5 phases in sdlc:
1)requirement & analysis
2)design
3)coding
4)testing
5)maintainance

1)requirement & analysis:
the main aim of requirement analysis phase is to produce
a document that properly specifies all reuirements of the
customer.
requirement specification document is the primary out put
of this phase.
proper requirements and analysys are critical for having
succesful project.
the need for executing this phase properly to produce an
srs with the least defect should be evident.

2)design: during the design phase the user requirements are
elicited and software satisfying these requirements are
designed built tested,delivered to the customer.

high level:high level design is the phase of life cycle
the logical view of computer implementation of solution to
the customer requirements are developed.it gives the
solution at high level of abstraction.during the high level
design the functional architecture of application and
database design takes place.
the entry criteria is that srs has been reviewed and
authourised. the input for this phase is software
requirement specification and output for this phase is high
level design document. the exit criteria is that the high
level design document has been reviewed and authourised.

low level design:the view of the application developed in
the high level design is broken into modules and logic
design is done for every program .a unit test plan is
created and documented as program specification. the
important activity in the detailed design phase is
identification of common routines and programs.

the entry criteria is that the highlevel design document
has been reviewed and authourised.
the exit criteria is that the program specification
document has been reviewed and authourised.

coding:
during the coding phase required programing language is
used to produce the program.this phase produces source
code, executables and database design.

testing:
here actual testing takes place .

maintainance:
succesfully developed project will undergo for maintainance.