Object-Oriented Programming

Object-Oriented Programming (OOP), in computer science, is a type of high-level computer language that uses self-contained, modular instruction sets for defining and manipulating aspects of a computer program. These discrete, pre-defined instruction sets are called objects and may be used to define variables, data structures, and procedures for executing data operations. In OOP, objects have built-in rules for communicating with one another. They can also be manipulated or combined in various ways to modify existing programs and to create entirely new ones from pieces of other programs. The most popular OOP language is C++. In May, 1995 a new OOP language Java was released. It has drawn worldwide interest. In some ways Java represents a simplified version of C++, but it adds other features and capabilities as well, and is particularly well suited for writing interactive applications to be used on the World Wide Web.

Ex. 6. Look at the table and answer the questions:

1. Who invented Java? 2. When was Java developed? 3. Can Java run on any computer (Mac, PC or UNIX workstation)? 4. What are Java’s small programs called? What can you do with them?

Language	Date	Characteristics	Uses
Java invented by Sun Microsystems	1995	Cross-platform language that can run on any machine. Small Java programs, called “applets”, let you watch animated characters, play music and interact with information	Designed to create Internet applications. When you see a Web page containing Java links, a Java program is executed automatically.

Ex. 7. Listen to the dialogue. Complete the Table with the relevant information.

Developed by	Date	Characteristics	Uses	Extensions
Dennis Ritchie at …		Created to replace … The language is small, …	Originally designed for … Today it is used to …	C++ and … Object-oriented language

Ex. 8. Answer the questions.

1. Are programming languages artificial or natural? 2. What type of programming languages do you know? 3. What programming languages are preferable to programmers? 4. What programming languages can you name?5. Which of them do you like best? 6. What programming languages have you already worked with? 7. What are the differences between them?

Unit 8 operating system The Definition of the os

An operating system (commonly abbreviated as OS and O/S) is the software component of a computer system that is responsible for the management and coordination of activities and the sharing of the resources of the computer. It is the most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. For large systems, the OS has even greater responsibilities and powers. It is like a traffic cop (гаишник) – it makes sure that different programs and users running at the same time do not interfere with each other. The OS is also responsible for security, ensuring that unauthorized users do not access the system. Almost all computers, including hand-held computers, desktop computers, supercomputers and even modern video game consoles, use an operating system of some type.

Operating systems can be classified as follows:

• Multi-user (многопользовательские): allow two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.

• Multi-processing: support running a program on more than one CPU.

• Multi-tasking: allow more than one program to run concurrently (одновременно).

• Real time: respond to input instantly (реагируют на вход мгновенно).

Operating systems provide a software platform on top of which other programs, called application programs (прикладные), can run. The application programs must be written to run a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are Windows, OS/2, Linux.

As a user, you normally interact with the OS through a set of commands. For example, the DOS operating system contains commands such as COPY and RENAME for copying files and changing the names of files, respectively. The commands are accepted and executed by a part of the operating system called the command processor or command line interpreter. Graphical user interfaces allow you to enter commands by pointing and clicking at objects that appear on the screen.