Traditional
and Structural programming
This is the first programming approach used in the
beginning. Structure programming is associated with top down approach to
design. So large routines are broken down into smaller modular routines. Here,
designer converts the large structure of a program in terms of smaller
operation and implement and test the smaller operation and then tie them
together into a whole program.
Program is divided into several basic structure and these
structure are called build blocks. They are:
- Sequential Structure
This contain program statement one
after another
- Selection or Conditional Structure
The program has many condition from which correct condition
is selected to solve the problem.
- Repetition or Loop Structure
The process of repetition or iteration repeats statement
blocks for several times when the condition is matched.
Advantages of
Traditional Approach
Problem can be easily described
Testing and debugging is easy
Easy to modify and maintain
The program is easily coded using
modules.
SDLC (Software
Development Life Cycle)
In market different kinds of general purpose software
package are available but sometimes these packages ca not fulfill all clients’
requirements. So to fulfill the clients requirements new software must be
developed generally the client comes to the developers’ site with their
problems to be solved and to find computer based solution. To develop good
quality of software it is required to go through following phases.
1. Problem Analysis:- It is important to give a clear concise problem
statement. It is also called problem definition. The problem should clearly
specify the following tasks.
-Objectives:- The problem should be stated clearly so that there
will not be the chance of having right solution to the wrong problem. Simple
program can be stated easily and early but for complex program we need the
complex analysis with careful co-ordination of people, procedure and programs.
- Output Requirements:- Before we know what should go into system, we
must know what should come out from the system being developed. Although system
analysist or programmer, the best person
to design output is the end users. So it is better of designing output with the
end users.
- Input requirements:- To get the above design output it is required
to define the input data and source of input data. for example in student
information system input data may be student records and source may be the
college administration.
- Processing requirement:-
It is required to clearly define processing requirements to convert the given
input data to the required output. In processing requirement there may be
hardware platform, software platform, manpower etc.
- Evaluating feasibility:- It is one of the most important phase where
we mainly decide whether the purposed software development task is technically
and economically feasible or not. Before development availability of hardware
needs to be checked whether the client can afford the software or not. Finally
there should be the proper documentation of different task of problem analysis
done in above stages.
a. Algorithm
An algorithm is a finite set of instruction written in a
sequence that should be followed to solve the given problem all algorithm must
satisfy the following criteria.
Input:- one or more quantity are externally supplied for processing
which is known as inputs
Output:-after input are process, they must produce at least one
quantity as output
Unambiguous:- each instruction in algorithm must be cleared. It
should not have double meaning.
Fineness:-the algorithm should terminated after a finite no of
steps.
b. Flowchart: it is
a diagrammatic representation of the procedure for solving the problem or it is
a graphical representation of an algorithm. It consist of set of symbols for
different function which help a programmer to solve a given problem. The
various symbols used in preparation of flowchart are stated as below.
3. Coding: - The algorithm and flowchart cannot be read by the
computers it first must be written in programming language to develop a
computer program. Coding can be done in high level language and most of
programmer used high level language in these days. Easily readable, reliable,
proper error handling and easy to maintenance and support after installation
are the feature of the efficient program.
Compilation and Execution: - program written in high level language
needs to be converted into low level language and compilation does these tasks.
Code that is ready to run is called execution table code or machine code.
4. Debugging and Testing:- Debugging
and testing is the process of detecting and removing errors in a program so
that the programmer produce the desire result on all occasion.
1. Syntax error
2. Runtime error
3. Logical error
Debugging is the process of isolating and correcting any type of
above discussed error. Testing is
the process of executing a program or system with the intension of finding
error. Typically more than 50% of development time is spend in testing. Testing
is usually performed for the following purpose.
- To improve
quality
- For
verification and validation
- For reliability
estimation
- A program
analysis document with objectives, input, output and processing procedure.
- Program design
document, algorithm and detail flowchart and other appropriate diagrams.
- Program verification
document with details of checking, testing and correction procedure along with
the list of test data.
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