Computer Language

Computer Language

The term computer language includes a wide variety of languages used to communicate with computers. Different kinds of languages have been developed to perform different types of work on the computer. Basically languages can be divided into two categories. Two basic types of computer languages are:

1. Lower-level language

A language that corresponds directly to a specific machine. There are two types of low-level languages.

Machine language

A language that is directly understood by the hardware. Machine language is the lowest and most Elementary level of programming language. It was the first type of programming language to be developed. It uses binary digits '0' and '1' for giving instructions.

Assembly Language

A slightly more user-friendly language that directly corresponds to machine language. Assembly Language was developed to overcome some of the many inconveniences of machine language. This is another new level but very important language in which operation codes and operands are given in the form of alphanumeric symbols instead of 0 and 1. It is called mnemonics (nodes). Because of this feature Assembly Language is also known as symbolic programming language.

2. High-level language

Any language that is independent of the machine. Types of high-level languages are BASIC (beginners all-purpose symbolic instruction code), Fortran (Formula Translation), Pl/1 (Programming Language/one), ALGOL (Algorithmic Language), C, C++, JAVA etc. High-level languages allow a user to give instruction in the English language which makes them easier to learn. Programs developed on one system can be executed on other systems and will produce the same outputs. It uses the translator program for converting the high-level program into machine language. Compiler and interpreter are used as translators in HLL.

Compiler

Compiler is a translator program that converts to the whole HLL Source program into object code, machine program code at once and also generates list of errors and shows it to the user.

Interpreter

Interpreter is translator program that convert HLL programs line by line. If there is any error at any point or line, program execution will stop until error is removed or debugged.

4GL (Fourth Generation Language)

This generation of language allows non-programmer users to write program to query databases and to generate custom reports. Characteristics of 4GL

• User-friendly
• Execution is fast
• Easy to learn and program by non-programmer user
• Uses of artificial intelligence and neural network
• 4GL are closer to human language than other high-level languages and are accessible to people without formal training as programmers. Clarion, Data flax, Forte Tool are example of 4GL.

Short Notes:

Comparison on human language and computer language

SN	Human Language	SN	Computer Language
1	Vocabulary	1	Keywords/ Reserved Words
2	Grammar	2	Syntax
3	Meaning/ Sense	3	Semantic

Generation of Computer Language

1st Generation Language - Machine Language

• It is the least level language,
• The instruction are written in the form of series of 1's and 0's,
• It is directly understood by computer,
• It is time consuming for encoding and decoding,
• It is quite difficult to write and understand,
• It is machine dependent i.e. varies from one system architecture to another architecture.

2nd Generation Language - Assembly Language

• It uses symbolic code (Mnemonic Code) and Binary Code (Machine Code 1's or 0's),
• It is also machine dependent language,
• It is quite easier than machine language,
• It is also called low level language.

3rd Generation Language - High Level Language

• More approach to human language,
• It uses English language for instructions.
• Procedural Language/ Procedural Oriented Language
• Most of the programming language falls on this categories. Example, COBOL, FORTRAN... etc.

4th Generation Language

• Problem Oriented Language/ Non-procedural Language
• Most of all database system falls on this categories.

5th Generation Language Natural Language

Instructions are in the form of human voice (human language). Example, Prolog (program logic)

   Language Processors or Translators

It is the system software that translates source code to object code.

Types of Translator/ Language Processor

1. Assembler
2. Compiler/ Interpreter

Assembler

It is the system software that translates a source code/program written in assembly language into machine code.

Compiler/Interpreter

It is the system software that translates a source code/program written in high level language into machine code.

Difference between Compiler and Interpreter

SN	Compiler	Interpreter
1	Compiler works on the complete program at once. It takes the entire program at once.	Interpreter program works line-by-line. It takes one statement at a time as input.
2	Compiler generates intermediate code, called the object code or machine code.	Interpreter does not generate intermediate object code or machine code.
3	Compiler executes conditional control statements (like if-else and switch case) and logical constructs faster than interpreter.	Interpreter executes conditional control statements at a much slower speed.
4	Compiled programs take more memory because the entire object code has to reside in memory.	Interpreter does not generate intermediate object code. As a result, interpreter programs are more memory efficient.
5	Compile once and run anytime. Compiled program does not need to be compiled every time.	Interpreted programs are interpreted line-by-line every time they are run.
6	Errors are reported after the entire program is checked for syntactical and other errors.	Error is reported as soon as the first error is encountered. Rest of the program will not be checked until the existing error is removed.
7	A compiled language is more difficult to debug.	Debugging is easy because interpreter stops and reports errors as it encounters them.
8	Compiler does not allow a program to run until it is completely error-free.	Interpreter runs the program from fist line and stops execution only if it encounters an error.
9	Compiled languages are more efficient but difficult to debug.	Interpreted languages are less efficient but easier to debug. This makes such languages an ideal choice for new students.
10	Examples of programming languages that use Compilers: C, C++, COBOL	Examples of programming languages that use interpreters: BASIC, Visual Basic, Python, Ruby, PHP, Perl, MATLAB, Lisp

Bug

• The error of computer program.
• Error in computer language.

Debug

The process of eliminating error (bug).

Types of Bugs

1. Syntax Error

• Due to the structure of instruction or reserved word.
• It is signaled by translator.

     2. Logical Errors

• Due to the logic of programmer.

     3. Runtime Errors

Due to hardware fault.