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 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 corresponds to several machine code instructions.
As high-level languages are a method of writing programs using English like
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.
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».
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.
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