Information Technology and Systems
<< Previous Chapter
Chapter 7 : Program Design and Programming Languages
Program Development Lifecycle
Defining the Problem
Designing the Program
Coding the Program
Testing and Debugging the Program
Formalizing the Solution
Maintaining the Program
Program Design Tools
Flow Charts
Decision Tables
Control Structures
Pseudocode
Generations of Programming Languages
First Generation Languages
Second Generation Languages
Third Generation Languages
Fourth Generation Languages
Fifth Generation Languages
Language Translators and Programming Languages
Language Translators
Programming Languages
Object-Oriented Programming - An Overview
Basic Concepts in Object-Oriented Programming
Chapter Summary
|
Computer software is a set of programming instructions. Before starting
coding, programmers must understand the user requirements and the flow of
logic of the program. Software developers can use the Program Development
Lifecycle (PDLC) to define the program structure. The six phases of PDLC are
defining the problem, designing the program, coding the program, testing and
debugging the program, formalizing the solution, and maintaining the
program. Program designing begins with deciding the output and framing the
program logic. The design is then broken down into modules to facilitate
programming.
All computer languages have a vocabulary of their own. If a programmer does
not strictly follow the syntax of a programming language, the computer will
not understand the commands given in the program. Programming languages
generally fall into two categories – low-level languages and high-level
languages. Machine languages and assembly languages are low-level languages. |
|
Low-level languages are hardware friendly. First generation languages and
second generation languages are regarded as low level languages, whereas the
languages of higher generations are regarded as high-level languages.
A machine language consists of binary numbers (0s and 1s) which respond
directly to the on and off electrical pulses generated by the computer. It
is also called the first generation programming language. Assembly language
is easier to use than machine language as a programmer can use symbols to
sum up program instructions. High-level languages free programmers from the
need to know the details of a processor, but they still require programmers
to specify the procedure to be followed to solve a problem.
Fourth-generation languages free programmers from worrying about the
procedures to be followed to solve a problem, but most of them are
restricted to the use of accessing databases. An application generator
facilitates the development of applications. It includes defining input
transactions, editing such transactions, creating a database, updating
files, generating reports, and processing queries. The fifth generation
programming languages are designed to enable the computer to solve a
problem. These languages incorporate concepts like artificial intelligence,
expert systems, etc.
Language translators convert a source code into an object code. The two
types of translators are compilers and interpreters. A compiler is a
translation program which translates the entire source code of a high-level
programming language into an object code and creates an object file. An
interpreter is a program that executes the instructions which are written in
a high-level language.
Different types of programming languages serve different purposes. Some of
the programming languages which are popularly used include COBOL, BASIC,
Pascal, C, Ada, C++, Visual Basic and Java.
Object-oriented programming is a programming technique designed to provide
component reusability. The basic concepts of object-oriented programming are
objects and classes, abstraction, encapsulation, polymorphism, and
inheritance.
Next Chapter>>
|
|
Short Case Studies / Caselets