Programming Language

Defination

An artificial and formal language that has a limited vocabulary consisting of set of keywords for making up instruction and a set of precise grammar rules 

Classification 

* Special Purpose :
   designed for a particular class of application : SQL data retrieval 

* General Purpose:
   can be used to obtain solutions for many different types of problem (machine language, assembly language and high level language) 

Machine Language 

- the only language the processor actually understand

- consist of binary codes: 0 and 1

- Ex: 1101 0001 1000 0101 1000 0110 1111 0001

- each of the lines above corresponds to a specific task to be done by the processor

- programming in machine code is difficult and slow since it is difficult to memorize all the instructions.     Mistakes can happen very easily 

- Processor dependent and not portable 

Assembly Language 

- enable machine code to be represented in words and numbers

- example of a program in assembly language:

   LOAD A, 9999

   LOAD B, 8282

- cannot be processed directly by a computer, must be converted to machine language using assemblers

- easier to understand compared to machine code but still is quite difficult to use

- each instruction corresponds to a specific machine code : lengthy programs

- processor dependent and not portable 

High Level Language 

- use more English word and numbers - it easier to understand

- the programming structure is problem oriented = does not need to know how the computer actually 

   execute the instructions

- processor independent - the same code can be run on different processors

- high level languages must be converted into machine code to be executed by the processor.

- example : FORTRAN, COBOL, BASIC, Pascal, Ada, C, C++, Java