Know About Programming Language Generation (Important)
Programming languages have been classified into several programming language generations. Historically, this classification was used to indicate increasing power of programming styles. Later writers have somewhat redefined the meanings as distinctions previously seen as important became less significant to current practice.
First and second generation
The terms "first generation" and "second generation" programming language were not used prior to the coining of the term "third-generation"; none of these three terms are mentioned in early compendiums of programming languages. The introduction of a third generation of computer technology coincided with the creation of a new generation of programming languages. The marketing for this generational shift in machines correlated with several important changes in what were called high level programming languages, discussed below, giving technical content to the second/third-generation distinction among high level programming languages as well, and reflexively renaming machine code languages as first generation, and assembly languages as second generation.
Second-generation programming language (2GL) is a generational way to categorize assembly languages. The term was coined to provide a distinction from higher level third-generation programming languages (3GL) such as COBOL and earlier machine code languages. Second-generation programming languages have the following properties:
- The code can be read and written by a programmer. To run on a computer it must be converted into a machine readable form, a process called assembly.
- The language is specific to a particular processor family and environment.
Second-generation languages are sometimes used in kernels and device drivers (though C is generally employed for this in modern kernels), but more often find use in extremely intensive processing such as games, video editing, graphic manipulation/rendering.
One method for creating such code is by allowing a compiler to generate a machine-optimized assembly language version of a particular function. This code is then hand-tuned, gaining both the brute-force insight of the machine optimizing algorithm and the intuitive abilities of the human optimizer.
Third generation Programming Language
A third-generation programming language (3GL) is a generational way to categorize high-level computer programming languages. Where assembly languages, categorized as second generation programming languages, are machine-dependent, 3GLs are much more machine independent and more programmer-friendly. This includes features like improved support for aggregate data types, and expressing concepts in a way that favors the programmer, not the computer. A third generation language improves over a second generation language by having the computer take care of non-essential details. 3GLs feature more abstraction than previous generations of languages, and thus can be considered higher level languages than their first and second generation counterparts.
First introduced in the late 1950s, Fortran, ALGOL, and COBOL are early examples of this sort of language.
Most popular general-purpose languages today, such as C, C++, C#, Java, BASIC and Pascal, are also third-generation languages, although each of these languages can be further subdivided into other categories based on other contemporary traits.
Most 3GLs support structured programming.
A programming language such as C, FORTRAN, or Pascal enables a programmer to write programs that are more or less independent from a particular type of computer. Such languages are considered high-level because they are closer to human languages and further from machine languages. In contrast, assembly languages are considered low-level because they are very close to machine languages.
The main advantage of high-level languages over low-level languages is that they are easier to read, write, and maintain. Ultimately, programs written in a high-level language must be translated into machine language by a compiler or interpreter.
The first high-level programming languages were designed in the 1950s. Examples of early high level languages are ALGOL, COBOL, and FORTRAN. These programs could run on different machines so they were machine-independent. As new, more abstract languages have been developed, however, the concept of high and low level languages have become rather relative. Many of the early "high level" languages are now considered relatively low level in comparison to languages such as Python, Ruby, and CommonLisp.
Fourth generation Programming Language
A fourth-generation programming language (4GL) is a computer programming language envisioned as a refinement of the style of languages classified as third-generation programming language (3GL). Each of the programming language generations aims to provide a higher level of abstraction of the internal computer hardware details, making the language more programmer-friendly, powerful and versatile. While the definition of 4GL has changed over time, it can be typified by operating more with large collections of information at once rather than focusing on just bits and bytes. Languages claimed to be 4GL may include support for database management, report generation, mathematical optimization, GUI development, or web development. Fourth-generation languages have often been compared to domain-specific languages (DSLs). Some researchers state that 4GLs are a subset of DSLs.
In the 1980s and 1990s, there were efforts to develop fifth-generation programming languages (5GL).
Fifth generation Programming Language
A fifth generation programming language (abbreviated as 5GL) is a programming language based on solving problems using constraints given to the program, rather than using an algorithm written by a programmer. Most constraint-based and logic programming languages and some declarative languages are fifth-generation languages.
While fourth-generation programming languages are designed to build specific programs, fifth-generation languages are designed to make the computer solve a given problem without the programmer. This way, the programmer only needs to worry about what problems need to be solved and what conditions need to be met, without worrying about how to implement a routine or algorithm to solve them. Fifth-generation languages are used mainly in artificial intelligence research. Prolog, OPS5, and Mercury are examples of fifth-generation languages.
These types of languages were also built upon Lisp, many originating on the Lisp machine, such as ICAD. Then, there are many frame languages, such as KL-ONE.
In the 1980s, fifth-generation languages were considered to be the way of the future, and some predicted that they would replace all other languages for system development, with the exception of low-level languages. Most notably, from 1982 to 1993 Japan put much research and money into their fifth generation computer systems project, hoping to design a massive computer network of machines using these tools.
However, as larger programs were built, the flaws of the approach became more apparent. It turns out that, given a set of constraints defining a particular problem, deriving an efficient algorithm to solve it is a very difficult problem in itself. This crucial step cannot yet be automated and still requires the insight of a human programmer.