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.
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A first-generation (programming) language (1GL) is a grouping of programming languages that are machine level languages used to program first-generation computers. Originally, no translator was used to compile or assemble the first-generation language. The first-generation programming instructions were entered through the front-panel switches of the computer system.
The instructions in 1GL are made of binary numbers, represented by 1s and 0s. This makes the language suitable for the understanding of the machine but far more difficult to interpret and learn by the human programmer.
3GLs are much more machine-independent (portable) 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 are more abstract 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 examples of early 3GLs.
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. Many support object-oriented programming. Traits like these are more often used to describe a language rather than just being a 3GL.
Fourth-generation languages tend to be specialized toward very specific programming domains.[4][5] 4GLs may include support for database management, report generation, mathematical optimization, GUI development, or web development.
A fifth-generation programming language (5GL) is any programming language based on problem-solving using constraints given to the program, rather than using an algorithm written by a programmer.[6] Most constraint-based and logic programming languages and some other declarative languages are fifth-generation languages. It uses Artificial Intelligence or (AI) technology to solve problems on its own.
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 user 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 or AI research. OPS5 and Mercury are examples of fifth-generation languages,[7] as is ICAD, which was built upon Lisp. KL-ONE is an example of a related idea, a frame language.
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 while retroactively renaming Machine code languages as first generation, and assembly languages as second generation.
Initially, all programming languages at a higher level than assembly were termed "third-generation", but later on, the term "fourth-generation" was introduced to try to differentiate the (then) new declarative languages (such as Prolog and domain-specific languages) which claimed to operate at an even higher level, and in a domain even closer to the user (e.g. at a natural-language level) than the original, imperative high-level languages such as Pascal, C, ALGOL, Fortran, BASIC, etc.
"Generational" classification of high-level languages (third generation and later) was never fully precise and was later perhaps abandoned, with more precise classifications gaining common usage, such as object-oriented, declarative and functional. C gave rise to C++ and later to Java and C#; Lisp to CLOS; Ada to Ada 2012; and even COBOL to COBOL 2002. New languages have emerged in that "generation" as well.
C is a general-purpose, high-level language that was originally developed by Dennis M. Ritchie to develop the UNIX operating system at Bell Labs. C was originally first implemented on the DEC PDP-11 computer in 1972.
The source code written in source file is the human readable source for your program. It needs to be "compiled", into machine language so that your CPU can actually execute the program as per the instructions given.
C programming language also allows to define various other types of variables, which we will cover in subsequent chapters like Enumeration, Pointer, Array, Structure, Union, etc. For this chapter, let us study only basic variable types.
This structure requires 8 bytes of memory space but in actual, we are going to store either 0 or 1 in each of the variables. The C programming language offers a better way to utilize the memory space in such situations.
The last chapter explained the standard input and output devices handled by C programming language. This chapter cover how C programmers can create, open, close text or binary files for their data storage.
A file represents a sequence of bytes, regardless of it being a text file or a binary file. C programming language provides access on high level functions as well as low level (OS level) calls to handle file on your storage devices. This chapter will take you through the important calls for file management.
As such, C programming does not provide direct support for error handling but being a system programming language, it provides you access at lower level in the form of return values. Most of the C or even Unix function calls return -1 or NULL in case of any error and set an error code errno. It is set as a global variable and indicates an error occurred during any function call. You can find various error codes defined in header file.
Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.
The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.
Sometimes, you may come across a situation, when you want to have a function, which can take variable number of arguments, i.e., parameters, instead of predefined number of parameters. The C programming language provides a solution for this situation and you are allowed to define a function which can accept variable number of parameters based on your requirement. The following example shows the definition of such a function.
This chapter explains dynamic memory management in C. The C programming language provides several functions for memory allocation and management. These functions can be found in the header file. 2ff7e9595c
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