Definition of High level language
High level language (HLL) is a computer programming language that is machine independent and designed to reflect the requirement of a problem. They look like the natural human understandable language or mathematical notation. HLL are also called Problem-Oriented Languages because they are used to solve problems. They require translators to translate them to machine language.
- Modes of translation
High level languages are translated to machine language by compilers or interpreters. They perform the translation in two different ways.
- Compiler
A compiler is a computer program that translates a whole source HLL source program (Code) into an executable machine language (binary numbers) code all at once before executing and bringing out the errors, i.e. a compiler translates all the program before running or execution.
- Interpreter
An interpreter is a program that translates and executes HLL source program one line at a time, it points out the error as it encounters it line after line and executes it immediately.
- Classification of High level language
High level languages can be classified in two ways. They are:
- By Purpose
- By the method of translation into Machine Language.
By purpose or type of the problem
In this category, a HLL is classified either as “General purpose” or “Specific purpose”.
A general purpose HLL is a HLL that is not designed to be used to program any particular application or problem. Some examples of such HLL language are C, JAVA, BASIC, PASCAL etc.
While a special purpose HLL is a HLL that is designed to program specific applications. Some examples of such HLL languages are
Scientific HLL: These are HLL that are designed to solve scientific problems. E.g. AlGOL, FOTRAN
HTML: It’s a special purpose HLL for developing websites.
PostScript: It’s a special purpose HLL for presenting 2-dimensional objects like cartoons.
Artificial Intelligence: It’s a special purpose HLL for programming robots and solving artificial intelligence problems like LISP, PROLOG and so on.
SNOBOL: It’s a special purpose HLL for manipulation of text.
Command Languages: are used to communicate with the operating systems.
By Method of Translation.
When languages are classified by the mode of translation, we would have interpreted and compiled languages.
An Interpreted Language is a language that uses an interpreter to translate to ML, some examples of such programs are BASIC, LISP, JAVA, C#, Python, PERL, MATLAB, PASCAL and Ruby. The main disadvantage of interpreted language is that it runs slower than a compiled language. However they save a lot of time while developing and testing programs. While Compiled Language is a language that uses a compiler to translate to machine language. Examples are FORTRAN, COBOL, C.
ASSIGNMENTS
- State three (3) advantages and one disadvantage of an interpreter.
- List nine (9) features of BASIC, C, PASCAL, COBOL program languages.
- State four (4) advantages of HLL over ML and LLL.
No comments:
Post a Comment