SOFTWARE DEVELOPMENT

Software Development

A program is a solution developed to solve a particular problem, written in a form that can be run on a computer. Therefore, writing a program is almost the last step in a process that first determines the problem to be solved and the method to be used in the solution. Each field of study has its own name for the systematic method of designing solutions to solve problems.

In science and engineering, the approach is referred to as the scientific method, and in quantitative analysis, the approach is called the systems approach. Professional software developers use the software development procedure for understanding the problem to be solved and for creating an effective, suitable software solution.

1. Development and design 2. Documentation 3. Maintenance

PHASES OF SOFTWARE DEVELOPMENT

As a discipline, software engineering is concerned with creating readable, efficient, reliable, and maintainable programs and systems, and it uses the software development procedure to achieve this goal.

Phase I: Development and Design Phase

It begins with a statement of a problem or a specific request for a program, which is referred to as a program requirement. After a problem has been stated or a specific request for a program solution has been made, the development and design phase begins. This phase consists of four well-defined steps.

Step 1: Analyze the Problem The analysis of a problem can consist of up to two parts. The first part is a basic analysis that must be performed on all problems; it consists of extracting the complete input and output information supplied by the problems. For this analysis, you must: 1. Determine and understand the output items the program must produce. 2. Determine the input items.

An extended analysis simply means you must gather more information about the problem so that you thoroughly understand what’s being asked for and how to achieve the result.

Step 2: Develop a Solution

Next, you select the exact set of steps, called the algorithm, to use for solving the problem. This algorithm must be checked, if it wasn’t in the analysis step, to make sure it produces the required outputs correctly.

For these specifications, a designer could initially organize the program’s requirements into the three sections.

Step 3: Code the Solution (Write the Program)

These structures control how the program executes and consist of the following types:

• Sequence • Selection • Iteration • Invocation

Sequence defines the order in which the program executes instructions. Specifying which instruction comes first, which comes second, and so on is essential if the program is to achieve a well-defined purpose.

Selection provides the capability to make a choice between different operations, depending on the result of some condition.

Iteration, also referred to as “looping” and “repetition,” makes it possible to repeat the same operation based on the value of a condition.

Invocation involves invoking, or summoning, a set of statements as it’s needed.

Step 4: Test and Correct the ProgramThe purpose of testing is to verify that a program works correctly and actually fulfills its requirements. In theory, testing would reveal all existing program errors.