Thursday, March 31, 2011

CHAPTER14 - PROGRAMMING AND LANGUAGES

PROGRAMMING LANGUAGES 

  • artificial language designed to express computations that can be performed by a machine, particularly a computer
  • used to create programs that control the behavior of a machine, to express algorithms precisely, or as a mode of human communication.
  • The first programming languages predate the modern computer.
  • The 19th century had "programmable"looms and player piano scrolls which implemented what are today recognized as examples of domain-specific languages.   
  • In the 1940s, the first electrically powered digital computers were created.  
  • The first high- level programming languages to be designed for a computer was Plankalkul , developed for the German Z3 by Konrad Zuse between 1943 and 1945.   


                       http://www.mylot.com/w/photokeywords/programming+language.aspx                                    




Specification of Programming Languages

  • intended to provide a definition that the language users and the implementors can use to determine whether the behavior of a program is correct, given its source code. 
  • A programming language specification can take several forms, including the following:  
  1. An explicit definition of the syntax, static semantics, and execution semantics of the language
  • While syntax is commonly specified using a formal grammar, semantic definitions may be written in natural language (e.g., as in the C language)  
     2.  A reference or model implementation  , sometimes written in the language being specified  

  • The syntax and semantics of the language are explicit in the behavior of the reference implementation. 
  • Example : Prolog or ANSI REXX  
     3.  A description of the behavior of a translator for the language  

  • The syntax and semantics of the language have to be inferred from this description, which may be written in natural or a formal language.   
  • Example : the C++  and Fortran specifications  
What Does a Programming Languages Do?

  • A programming language is used to write computer programs such as : 
  1. applications 
  2. utilities 
  3. servers 
  4. systems programs 
  • A program is written as a series of human understandable computer instructions that can be read by a compiler and linker, and translated into machine code so that a computer can understand and run it.  
Examples Of Programming Languages

  1. These languages include Assembler, C or C++
  2. Operating systems like Linux or Windows are written in C and C++.   
  3. In the late 40s and early 50s, computer programs were entered by flicking switches.  
  4. It was quickly realised how inefficient and slow that was and computer languages soon appeared.  
  5. Through the 60s and 70s, these languages :  
  • Fortran  
  • Cobol
  • Basic   
Programming Languages that Now Use 

  • Java and C++ with C# starting to gain popularity and C holding its own.
  • have many attempts to automate this process, and have computers write computer programs but the complexity is such that for now, humans still write the best computer programs.  
NEWS PROGRAMMING LANGUAGES

  • The widely used C++ programming language is about to be updated, as the ISO steering committee for the language has approved the final draft specifying its next version.    
  • The ISO/IEC Information Technology Task Force (ITTF) will review the steering committee's Final Draft International Standard (FDIS) will review and barring any complications, publish the draft later this year. 
  • It will be known as C++ 2011. 
  • Although sometimes derided for its complexity,  C++ appears to be the third most popular programming language in use today, trailing only Java and C,  according to the most recent Tiobe survey  of programming languages.

                    
                                                          http://www2.research.att.com/~bs/3rd.html  


                        
         http://malaysiacrunch.blogspot.com/2009/01/most-popular-programming-languages.html 

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