Computer program:
A Computer is a device that follows the instructions given to it. A
well-defined set of instructions given to the computer to solve a problem is
called program.
Any computer program is written in computer programming
language. A person who develops programs is called programmer.
Programming
Languages: A set of words and symbols used to write computer programs is
called programming languages. The programming languages are used to write
computer programs. A programming language is a mean of communication between
user and computer.
Main categories of
programming languages
There are two types of computer programming languages are
given:
- Low-Level Languages
- High-Level Language
Low-Level Languages: Low-Level
Languages are near to computer hardware and far from human languages. Low-Level
languages are divided into two categories:
1. Machine
Language
2. Assembly Language
Machine Language:
A type of language in which instructions are written in Binary form is called
machine language. It is the only language that is directly understood by the
computer. It is native language of the computer.
A program written in machine language can be executed very
fast by the computer. The computer does not need any language translator to understand
this language. The programs written in machine language are
machine-dependent (it depends on hardware: mean program in machine
language written for Motorola processor can not execute by Intel
processor). Every computer has its own machine language.
Machine language is difficult to understand. The process of
writing and modifying programs in Machine language takes a lot of time.
Assembly Language: Assembly
language is low-level language. Sometime it is also called intermediate
language. It is one set higher than machine language. In assembly language,
machine instructions are replaced with English-like words known as Mnemonics.
High-Level Language: A
type of language that is close to human languages is called High-Level
Language. The instructions in these languages are similar to English language
such as input and print etc.
Every High-Level Language defines a set of rules for writing
programs called Syntax. Each
instruction must be written according to the syntax of the language. Any error
in the program in indicated by the language translator. A program cannot be
converted into machine language if it contains any syntax error.
Commonly used
High-Level Language
C/C++: It is used
to write system programs and application software.
Java: It provides
strong features for networking programming.
FORTRAN: FORTRAN
stands for FORmula TRANslation. It has very powerful mathematical capabilities.
BASIC: BASIC
stands for Beginner All Purpose Symbolic Instruction Code . It was used mainly
by students to use the computer for solving simple problems.
COBOL: COBOL
stands for Common Business Oriented Language. It is specially designed for
business application.
Characteristics of
High-Level languages
Some important characteristics of high-level language are as
follows:
Easy to Learn:
High Level languages are closer to human languages and far from machine
language. These are English like languages and are easier to learn.
Easy to Error
Detection: High Level Languages are easy to read and modify. It makes
it easy to find errors in programs written in High Level languages.
Standardized Syntax:
The syntax of High Level languages are standardized. These languages describe a
well defined way of writing programs. Different organizations work to determine
standard syntax of these languages. An important organization is American
National Standard Institute also known as ANSI.
Deep Hardware
Knowledge not required: These languages do not require deep knowledge of
hardware or machine architecture. A programmer can write efficient programs
without deep knowledge of hardware. He can concentrate on solving the problem
rather than concerning the human machine interaction.
Machine Independence: High
level languages provide machine independence. It means that the programs written
in High Level language can be executed on different types of computer. For
example a program written in C can be executed on Intel Processors and Motorola
Processors.
More Programmers:
Programming in Low Level languages is very difficult. But High Level languages
are easy to learn. It encourages more people to learn these languages. So many
programmers of High Level languages are available.
Shorter Programs:
Programs written in High Level Languages are shorter than Low Level languages.
One instruction of High Level language is equivalent to many instructions of
Low level language.
Source code and Object
code
Source code: A
program is written in high-level language is called source cod. Source code is
also called source program. Computer cannot understand the statements of
high-level language. The source code cannot be executed by computer directly.
It converts into object code (Machine program) then executed.
Object code: A
program in Machine language is called object code. It is also called object program
or machine code. Computer understands object code directly.
0 comments:
Post a Comment