Unit ………….Object Oriented Languages.

1. Study the vocabulary

to evolve – развиваться, эволюционировать

to correspond to – соответствовать

particular – определённый, конкретный

to require – требовать

statement – выражение

compiler – компилирующая программа

object file – объектный файл (файл с промежуточным представлением отдельного модуля программы, полученный в результате обработки исходного кода компилятором)

procedure [prə'siːʤə]– процедура, механизм, алгоритм

attribute –определяющий признак; атрибут

to view – оценивать, обозревать

encapsulation – инкапсуляция (языковой механизм ограничения доступа к определённым компонентам объекта)

inheritance – наследование (механизм объектно-ориентированного программирования позволяющий описать новый класс на основе уже существующего, при этом свойства и функциональность родительского класса заимствуются новым классом)

polymorphism – полиморфизм (возможность объектов с одинаковой спецификацией иметь различную реализацию.)

to be bound – связанный

restrictive – ограниченный

ancestor – предшествующий элемент

incremental –увеличивающийся постепенно

descendent object –

to embed – встраивать

1. Read and translate the text Object Oriented Languages.

Computer programming languages have evolved continually over the years. This evolution is detailed in the following examples.

Assembly Language. The first computer programs were written in assembly language. This is a primitive type of language in which each statement corresponds to a single machine instruction. Assembly language is specific to a particular type of computer; moving the program to a different type of computer requires writing a whole new program. Assembly language programs are difficult to write, debug, and maintain.

High Order Languages. After assembly language, high order languages were developed; among the early ones were FORTRAN and BASIC. One statement in a high order language corresponds to a sentence in English. A program called a compiler reads the statements from a source file and generates a file containing machine instructions, which is called an object file. The object file can then be loaded and executed by the computer. A high order language is more portable than an assembly language program; the same source file can be compiled for any computer as long as a suitable compiler exists.

Structured Languages. The next step in the evolution of computer programming languages was the development of structured languages like C and the introduction of data structures. A data structure is an assembly of simpler data types into a single record. Structures also became more defined in the procedural part of the language. A function or procedure is a small part of a larger program that could be written to provide some basic operation on a data structure such as a record.

Object Oriented Languages. The next step in the evolution of computer programming languages, object orientation, was introduced in the Smalltalk language. Object orientation takes the concepts of structured programming one step further. Now, instead of data structures and separate program structures, both data and program elements are combined into one structure called an object. The object data elements are called attributes, while the object program elements are called methods. Collectively, attributes and methods are called the object's members. Usually, an object's methods are the only programs able to operate on the object's attributes.

With object orientation, a fundamental change came in the way programs are viewed. The earlier view was that data must be manipulated in some way to achieve a final result, and a program was viewed as a sequential means of performing the manipulations. From an object orientation perspective, a program is viewed as a group of objects that react to messages from the user, other programs, or other objects. This view led to the idea of event-driven programming; i.e. when event A happens, this object performs action B. A message is sent to an object by calling one of its methods.