Compiled languages include C, C++, Pascal and Ada. Programs written in these languages are translated into the machine code of a given computer before execution. The program interpretation in this case is limited to the interpretation of a set of run-time programs that simulate the elementary operations of the source language which have no close analogues in the machine language. The translator of a compiled language is the one program in which creating the most efficient executable programs is of primary importance.
Implementation of interpreted languages occurs through the use of software interpreter. Such languages are LISP, ML, Perl, Postscript, Prolog, Smalltalk. A translator, unlike a compiler, does not produce the machine code of the computer used, but an intermediate form of program. It is easier to execute than the original program and differs from the machine code itself. Due to the lengthy execution time caused by the use of a software interpreter, interpreted language translators are usually fairly simple programs.
The development of the World Wide Web and the emergence of the language Java have made changes to the previously constructed scheme. Java bears more similarities to Pascal and C++ than to LISP, but in most cases it is used as an interpreted language. The Java compiler produces an intermediate set of byte codes for the Java virtual machine. Transferring bytecodes to the local machine is more time-efficient than transferring the results of a program’s execution to the web server. However, the web server cannot predict the machine architecture of the host computer. Therefore, the browser creates a Java virtual machine that executes a set of Java byte-codes.
This chapter discussed the programming environments and language selection criteria. The choice of programming language during the creation of the program is a very important point, which affects very much – the speed of creating a program, the speed of testing, the ability to transfer to other platforms, the ability to quickly make changes, the speed of execution of the final product and so on. In this case, there is no ideal language – they all have their own positive and negative qualities, which will affect the development process in one way or another.
Nowadays, when writing a program, several languages are used. For example, the speed-critical parts are written in low-level languages, the graphical part – in high-level and slow languages. The universal languages C and C++ are also often used. However, their universality has a downside, the presence of many subtleties leads to difficulties in learning the language.
Thus, we can say that the criterion for the choice of environment and programming language are, on the one hand, the functionality the program must have, and on the other hand – the qualification of the programmer who writes it.
