Programming Languages

Programming Languages

1. High-level programming

   • Close to human language.
   • Require an interpreter, translator or compiler to convert human understandable program to computer readable language called machine code.
   • Translation
     • Assembler
       • Converts assembly language's source code into machine language.
       • A program that takes a higher-level language and converts it into a pattern of bits that the computer runs to produce results.
     • Compiler
       • Program that compiles source code into executable instructions that a computer can understand.
       • Compiles code and produces it in a new format before it runs
       • Generates error messages after searching all the errors of a program and then lists them.
       • Does not require a translator software.
       • Initially takes a large amount of time to analyse the source code, but once the compilation has taken place there is no need for any translation on subsequent runs of the program.
     • Interpreter
       • An interpreter is a program that executes programming code directly.
       • Converts a source code using a step-by-step, line-by-line and unit-by-unit basis into machine code.
       • Takes less time to analyse the source code, but overall program execution time is slower.
       • Client buying the software would need the translator software.
       • Continues translating the program until the first error is met, in which case it stops.
   • Advantages over low level
     • Debugging is easier in a high-level language.
     • High-level programming techniques are applicable everywhere even where computational resources are limited
     • Humans create fewer errors in high-level language than working with 1s and 0s.
     • Easier to read, write and maintain.
     • Length of program is small compared with low-level languages.

2. Low-level programming

   • Assembly language
     • eg. MOV #8, R2
     • Between machine and high level language
     • At the level of telling the processor what to do.
     • Designed to be easily translated into machine language.
     • Does not require a compiler or interpreter to run the program
   • Machine Language
     • eg. 10101111000110101
     • Lowest level of programming language.
     • Directly executable by a computer without the need for translation by a compiler or an assember
     • In the native language of the computer
   • Does not require translation.
     • The processor for which the language it was written in can be processed straight away with out translating. Saves time.