Write About Programming Languages?

Programming languages :

To communicate users languages are used

Languages are 2 types

1.      natural language

2.      programming language

Natural languages are used to communicate users.

ex : Telugu, English, etc

Programming languages are used to communicate user & computer.

Programming languages are divided into 2 types.

Machine Level Language :

In order to write a machine language program, a programmer has to remember all the operation codes of the computer and know in details what each code does and how it affects various registers in the     processor.

The main purpose of using computers is to solve problems computer user to concentrate on the development of good algorithms for solving problems rather than be concentrated with the details of the  internal structure of the computer.

Assembly Language:

In An assembly language, mnemonics are used to represent operation codes, and strings of characters to represent address. An assembly language is designed mainly to replace each machine code with an understandable mnemonic and each address with a simple alphanumeric string; it is matched to a particular computer’s processor structure. It is thus machine dependent. It is necessary for an assembly language programmer to know all details of a computer’s logical structure in order to write a program.

In order to execute an assembly language program on a computer, it should first be translated to its equivalent machine language program. The mnemonic operation codes should 

be converted to absolute numeric operation codes. The symbolic addresses of operands used in assembly language should also be converted to absolute numeric address. The translator which does this is known as an assembler.

The input to an assembler is the assembly language program and is known as the source program. Its output is the equivalent machine language program and is known as object program. The assembler is a system program which is supplied by the computer manufacturer.

The main advantage of using an assembly language for programming is the efficiency of the machine language program resulting from it.

The main disadvantages of assembly languages are:

a.       It is machine-dependent. Thus program written in one model of a computer cannot be executed on another model.

b.      An assembly language programmer must be an expert who knows all about the logical structure of the computer for which the program is written.

c.       Writing assembly language programs is difficult and time-consuming.

 High Level Programming Languages:

v  Algorithms are used to solve a problem

v  Algorithms are written in natural languages

v  Easy to write

v  Describe the nature of the data to be processed

v  Operators, control structures are used to solve a problem

v  High level languages are machine independent and need not to know internal structure of the computer.

High level languages are designed independent of the structure of a specific computer.

This facilitates executing a program written in such a language on different computers.

Each high level language is a program which translates it into the machine language of

the computer.

There are two approaches to writing language translators. One method is to take one statement of a high level language at a time and translate it into a machine instruction which is immediately executed. This is called an interpreter. The other approach of translation is to store the high level language program, scan it and translate the whole program into an equivalent machine language program. Such a translator is known as compiler.

Some High Level Languages:

Fortran:

FORTRAN stands for Formula Translation. The language was designed to solve scientific and engineering problems and is currently the most popular language among scientists and engineers.

Cobol:

COBOL stands for Common Business Oriented Language. COBOL is widely used programming language for business data processing.

Pascal:

The primary aim of providing a language which allows beginners to learn good problem solving and programming methods. Pascal has facilities to manipulate, not only numbers, but also vectors, matrices, strings of characters.

C Language:

C has been designed so that it has the advantages of a high level language, namely, machine independence. At the same time it providing only the bare essentials required in a language so that a translator it into an efficient machine language code. The first major use of C was to write an operating system known as UNIX. An aspect of C which makes it a powerful programming language is the access to the addresses in memory where variables are stored.

Why has C become popular? The reasons are:

1.      It is flexible and can be used to program a variety of application.

2.      It is efficient in the sense that the object code produced is concise. This is due to the fact that C is closer to machine language semantics.

3.      C compilers are widely available and inexpensive.

C++ Language:        

An object oriented version of C called C++ is the most popular OOP language. In an Object Oriented Program (OOP) an object is modeled by a collection of data structures and a set of procedures that can be performed on this data structure. It was designed as an extension of C and its popularity is mostly due to the popularity of C.

Java:

Which is an object oriented language. This language achieves machine independence by defining a Java Virtual Machine for which the compiler is written. By a virtual machine we mean a non-existent machine. Java is getting wide acceptance now as programming language to write applications for a network of heterogeneous computers.

Scripting Languages:

Scripting languages assume that a collection of useful programs, each perform a task, already exist. It has facilities to combine these components to perform a complex task.