UNIT 10
I. Look up in the dictionary how to pronounce the following words. Write them down in the dictionary.
|
flipping toggle awkward |
to comprise to declare |
a notation a source |
to issue a compiler |
ambiguity to retrieve |
II. Read the text and do the exercises that follow it.
Programming Languages
Programming has been with us for over 40 years but it wasn’t born at the time as the first computers. When the first early computers were built, there were no programming languages. First machines were initially programmed by flipping toggle switches and changing cables. Needless to say, this was a slow, awkward process. People began quickly searching for a better, faster way to issue instructions to the computer.
The result was what we call Programming Languages. The programming languages fall into three general categories. They are comprised of ones and zeros, and are directly understood or executed by hardware. Electronic circuitry turns these 0s and 1s into the operations the computer performs.
Assembly Languages are powerful programming tools because they allow programmers a large amount of direct control over the hardware. They offer programmers greater ease in writing instructions but preserve the programmer’s ability to declare exactly what operations the hardware performs. Assembly languages are machine-specific, or machine-dependent. Machine-dependent means the instructions are specific to one type of computer hardware. Assembly languages are still provided by most computer manufacturers – they can’t be translated and used on another computer. Assembly code for a Prime mini won’t work on a Digital mini. Assembly code can’t even be transferred between some machines built by the same manufacturer. For the most part, assembly languages are used by systems programmers to develop operating systems and their components.
So Assembly languages were the first bridge between the English Language and the computer’s binary language. The creation of high-level programming languages followed. A high-level language is a language in which each instruction or statement correspond to several machine code instructions.
As high-level languages are a method of writing programs using Englishlike words as instructions, they allow users to write in a notation with which they are familiar, e.g., Fortran in mathematical notation, Cobol in English.
High-level programming languages combine several machine language instructions into one high-level instruction. Low-level languages required only a single letter or a short mnemonic a term, or a word that is easy to identify, such as ADD for addition. High-level language requires just a single statement.
A Statement is an expression of instruction in a programming language. For example, PRINT FILE, TXT is a statement. A statement translates into one or more instructions at the machine language level. Each programming language includes a set of statement and a syntax. Syntax is the set of rules governing the language’s structure and statements. The syntax rules may include how statements are written, the order in which statements occur, and how sections of programs are organized.
FORTRAN was created in 1954 by John Backus. And it was one of the first high-level languages for FORmular TRANslator. Fortran allows programmers to calculate complex formulas with a few source code instructions. It is used for scientific and mathematical problems. The source program is written using combination of algebraic formulas and English statements of a standard but readable form.
Another high-level machine language is Cobol. Cobol was developed by the Conference on Data Systems Languages. Cobol was issued by the US Government Printing Office in 1960. Cobol stands for Common Business-Oriented Language. The source program is written using statements in English. It was made for business industry, government and education applications. This means that Cobol «has a place for everything» and requires programmers to «put everything in its place». Cobol programs are separated into four sections, called divisions:
1. The Identification Division (раздел идентификации) documents the program name, the programmer’s name (s), dates and any other important identification information.
2. The Environment Division (раздел оборудования) names the computer hardware, including the CPU and I/O devices.
3. Data Division (раздел данных) identifies all associated files and working storage sections of the program.
4. The Procedure Division contains all the instructions in the Cobol program.
Cobol divisions are further divided into paragraphs and sections. This structure helps programmers write code efficiently and with a minimum of repetition and confusion.
Algol was developed as an international language for the expression of the algorithms between individuals, as well as programming language. It was introduced in the early 1960s. Algol stands for ALGOrithmic Language. This language is used for mathematical and scientific use. An Algol program consists of data items, statements and declarations, organized into a program structure BASIC or the Beginners AU-purpose Symbolic Instruction Code, was developed over a period of years by professors John Kemeny and Thomas Kurtz and students in the computer science program at Dartmouth College. It was released in 1965. In most versions, BASIC is an unstructured language. The original Basic was easy to learn allowing computer users to write simple programs within a few minutes.
Basic uses five major categories of statements:
– Arithmetical statements allow users to use Basic like a calculator
– Input/ Output statements, including READ, DATA, INPUT and PRINT
– Control statements including GOTO, IF-THEN, FOR, NEXT and END control the sequence of instructions executed by the computer
– Other statements help document Basic programs and set up data dimensions respectively
– System Commands tell the operating system how to work with Basic programs
RUN means execute a program
LIST directs the computer to display a Basic program.
III. Fill in the gaps necessary words or expressions:
1. First machines were ..... by flipping toggle switches and ..... .
2. The programming languages fall into ..... .
3. They are comprised of ..... and ..... .
4. ..... are powerful programming tools.
5. Machine-dependent means ..... .
6. A high-level language is a language in which ..... .
7. ..... is an expression of instruction in a programming language.
8. ..... allows programmers to calculate complex formulas with a few source code instructions.
9. ..... stands for ALGOrithmic Language.
10. Basic uses ..... .
IV. Fill in the prepositions:
1. Programming has been ..... us for over 40 years.
2. People began searching ..... a better, faster way to issue instructions to the computer.
3. They offer programmers greater ease ..... writing instructions.
4. Assembly code ..... a Prime mini won’t work ..... a Digital mini.
5. Assembly languages were the first bridge ..... the English Language and the computer’s binary language.
6. A statement translates ..... one or more instructions ..... the machine language level.
7. System Commands tell the operating system how to work ... Basic programs.
V. Find the synonyms to the following words:
VI. Find the antonyms to the following words:
VII. Give appropriate definition of the following terms:
1. programming languages
2. Assembly Language
3. Cobol
4. Algol
5. Basic
VIII. Give the situation from the text in which the following words and expressions are used:
1. for over 40 years
2. slow, awkward process
3. three general categories
4. a large amount of direct control
5. machine-dependent
6. to develop operating systems and their components
7. combine several machine language instructions
8. a set of statements
9. a few code instructions
10. write code efficiently
IX. Answer the questions:
1. How were the first computers programmed?
2. What is an example of assembly language?
3. What does the term machine-dependent mean?
4. What is an assembly language primary used for?
5. What is a high-level language?
6. What does it combine?
7. What is a statement/syntax?
8. When was FORTRAN created? What is Fortran?
9. When was Cobol created? What is Cobol?
10. How many sections are Cobol separated into?
11. What is Algol (when was it developed and for what)?
12. What is Basic?
13. What are major categories of Basic?
X. Complete the table with the relevant information:
XI. Write a paragraph describing C+ +. You can start like this: C ++ is a high-level language developed....