Types of Programming Language

Low Level Language

First-generation language is the lowest level computer language. Information is conveyed to the computer by the programmer

as binary instructions. Binary instructions are the equivalent of the on/off signals used by computers to carry out operations. The language consists of zeros and ones. In the 1940s and 1950s, computers were programmed by scientists sitting before control panels equipped with toggle switches so that they could input instructions as strings of zeros and ones.

Advantages

Ø  Fast and efficient

Ø  Machine oriented

Ø  No translation required

     Disadvantages

Ø  Not portable

Ø  Not programmer friendly

Assembly Language

Assembly or assembler language was the second generation of computer language. By the late 1950s, this language had become popular. Assembly language consists of letters of the alphabet. This makes programming much easier than trying to program a series of zeros and ones. As an added programming assist, assembly language makes use of mnemonics, or memory aids, which are easier for the human programmer to recall than are numerical codes.

Assembler

An assembler is a program that takes basic computer instructions and converts them into a pattern of bits that the computer's processor can use to perform its basic operations. Some people call these instructions assembler language and others use the term assembly language In other words An assembler is a computer program for translating assembly language — essentially, a mnemonic representation of machine language — into object code. A cross assembler (see cross compiler) produces code for one processor, but runs on another.

As well as translating assembly instruction mnemonics into opcodes, assemblers provide the ability to use symbolic names for memory locations (saving tedious calculations and manually updating addresses when a program is slightly modified), and macro facilities for performing textual substitution — typically used to encode common short sequences of instructions to run inline instead of in a subroutine.

High Level Language

The introduction of the compiler in 1952 spurred the development of third-generation computer languages. These languages enable a programmer to create program files using commands that are similar to spoken English. Third-level computer languages have become the major means of communication between the digital computer and its user. By 1957, the International Business Machine Corporation (IBM) had created a language called FORTRAN (FORmula TRANslater). This language was designed for scientific work involving complicated mathematical formulas. It became the first high-level programming language (or "source code") to be used by many computer users.

Within the next few years, refinements gave rise to ALGOL (ALGOrithmic Language) and COBOL (COmmon Business Oriented Language). COBOL is noteworthy because it improved the record keeping and data management ability of businesses, which stimulated business expansion.

Advantages

Ø  Portable or machine independent

Ø  Programmer-friendly

Disadvantages

Ø  Not as efficient as low-level languages

Ø  Need to be translated

Examples : C, C++, Java, FORTRAN, Visual Basic, and Delphi.

Interpreter

An interpreter is a computer program that executes other programs. This is in contrast to a compiler which does not execute its input program (the source code) but translates it into executable machine code (also called object code) which is output to a file for later execution. It may be possible to execute the same source code either directly by an interpreter or by compiling it and then executing the machine code produced.

It takes longer to run a program under an interpreter than to run the compiled code but it can take less time to interpret it than the total required to compile and run it. This is especially important when prototyping and testing code when an edit-interpret-debug cycle can often be much shorter than an edit-compile-run-debug cycle.

Interpreting code is slower than running the compiled code because the interpreter must analyses each statement in the program each time it is executed and then perform the desired action whereas the compiled code just performs the action. This run-time analysis is known as "interpretive overhead". Access to variables is also slower in an interpreter because the mapping of identifiers to storage locations must be done repeatedly at run-time rather than at compile time.

COMPILER

A program  that translates source code into object code. The compiler derives its name from the way it works, looking at the entire piece of source code and collecting and reorganizing the instructions. Thus, a compiler differs from an interpreter, which analyzes and executes each line of source code in succession, without looking at the entire program. The advantage of interpreters is that they can execute a program immediately. Compilers require some time before an executable program emerges. However, programs produced by compilers run much faster than the same programs executed by an interpreter.

Every high-level programming language (except strictly interpretive languages) comes with a compiler. In effect, the compiler is the language, because it defines which instructions are acceptable.

Fourth Generation Language

Fourth-generation languages attempt to make communicating with computers as much like the processes of thinking and talking to other people as possible. The problem is that the computer still only understands zeros and ones, so a compiler and interpreter must still convert the source code into the machine code that the computer can understand. Fourth-generation languages typically consist of English-like words and phrases. When they are implemented on microcomputers, some of these languages include graphic devices such as icons and onscreen push buttons for use during programming and when running the resulting application.

Many fourth-generation languages use Structured Query Language (SQL) as the basis for operations. SQL was developed at IBM to develop information stored in relational databases. Examples of fourth-generation languages include PROLOG, an Artificial Intelligence language