C Programming: An Overview

C is a general-purpose programming language that is extremely popular, simple, and flexible to use. It is a structured programming language that is machine-independent and extensively used to write various applications, Operating Systems like Windows, and many other complex programs like Oracle database, Git, Python interpreter, and more.

History of C Programming

C was originally developed at Bell Labs by Dennis Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the most widely used programming languages, with C compilers available for practically all modern computer architectures and operating systems.

The Evolution of C Programming: A Comprehensive Timeline

C was originally developed by Dennis Ritchie at Bell Labs in the early 1970s as an augmented version of Ken Thompson's B. B was a simplified version of Martin Richards's BCPL, which was influenced by John McCarthy's Lisp.
C was used to re-implement the Unix operating system, which was also developed at Bell Labs by Thompson and Ritchie. Unix was originally written in assembly language, but C made it more portable and maintainable.
Another Bell Labs employee, Brian Kernighan, had written the first C tutorial, and he persuaded Ritchie to coauthor a book on the language³⁴. The book, titled The C Programming Language, was published in 1978 and became known as K&R C. It defined the core features and syntax of C, and provided many examples and exercises.
In 1983, the American National Standards Institute (ANSI) formed a committee to standardize C. The committee published the first official standard for C in 1989, which is known as ANSI C or C89. It introduced some new features and libraries, such as function prototypes, const and volatile qualifiers, and stdio.h.
In 1990, the International Organization for Standardization (ISO) adopted ANSI C as an international standard, which is known as ISO C or C90. It was identical to ANSI C except for some minor changes and additions.
In 1999, the ISO published a revised standard for C, which is known as C99. It added many new features and libraries, such as variable-length arrays, complex numbers, boolean type, designated initializers, and stdbool.h.
In 2011, the ISO published another revised standard for C, which is known as C11. It added more new features and libraries, such as static assertions, anonymous structures and unions, alignment support, threads, and stdatomic.h.
In 2017, the ISO published a minor revision of C11, which is known as C17 or C18. It fixed some defects and inconsistencies in C11, but did not introduce any new features.
In 2024, the ISO is expected to publish a major revision of C17, which is known as C23. It is still under development, but some of the proposed features and libraries are bounds checking interfaces, contracts, decimal floating-point arithmetic, modules, and stdjson.h.

Scope in C Programming

The scope of a variable in C is the block or the region in the program where a variable is declared, defined, and used. Outside this region, we cannot access the variable and it is treated as an undeclared identifier. The scope is the area under which a variable is visible. In C, all identifiers are lexically (or statically) scoped.

Key Features

The C programming language, developed by Dennis Ritchie in 1972, is a procedural language that has been widely used in various applications, from system programming to photo editing software. Here are some of the key features that make C a powerful and versatile language:

Procedural Language: C is a procedural language, meaning it follows a step-by-step approach. In a C program, predefined instructions are carried out, and a program may contain more than one function to perform a particular task.
Fast and Efficient: While newer languages like Java and Python offer more features, they also require additional processing, which can slow down performance. C, being a middle-level language, provides programmers with direct access to computer hardware, making it faster than dynamically typed languages.
Modularity: The concept of storing C code in the form of libraries for future use is known as modularity. Most of C's power comes from its libraries, which solve common problems.
Statically Typed: C is a statically typed language, meaning the type of variable is checked at the time of compilation, not at runtime. This requires programmers to specify the type of variables used each time they write a program.
General-Purpose Language: C is used in a wide range of applications, including operating systems (Windows, Linux, iOS, Android, OXS) and databases (PostgreSQL, Oracle, MySQL, MS SQL Server, etc.).
Rich Set of Built-in Operators: C has a rich set of built-in operators, which can be used to write complex or simplified programs.
Libraries with Rich Functions: C's robust libraries and functions make it easier for even beginner coders to write programs.
Middle-Level Language: C is considered a middle-level language as it combines the features of both high-level and low-level languages. It can be used for low-level programming, such as scripting for drivers and kernels, as well as for high-level programming, such as scripting for software applications.
Portability: One of the most significant advantages of C is that it is a machine-independent language. This means that C programs can be executed on different machines with little or no modification.
Easy to Extend: C language is easy to extend, meaning that a user can add their own functions to C library.

Benefits of C Programming

C is a middle-level language that combines the features of both high-level and low-level languages. It can be used for low-level programming, such as scripting for drivers and kernels, and it also supports functions of high-level programming languages, such as scripting for software applications. C is a structured programming language which allows a complex program to be broken into simpler programs called functions. It also allows free movement of data across these functions.

Pros:

Portable language: The C programs written in one computer can run on any computer without any change of the program code or having a slight change.
Building block for other languages: The C program acts as the building block for other programming languages.
Structured programming language: A C program is a procedure-oriented language with a collection of function modules and blocks that form a complete program.
Easy to learn: It is very easy to learn the C language and acts as the basis for understanding other complex languages.
Built-in functions: C language gives you the opportunity to use several built-in functions in the C library to develop a program.
User-defined function: Apart from the standard function in the C library, you can create your own user-defined function to solve a specific problem.

Cons:

Data security: There is a lot of buffer overflow in the C language and this can lead to overwriting the information in the memory.
No run-time checking: The C language does not allow runtime checking making it difficult to fix the bugs if you extend the program.
No strict type checking: When passing data to the parameters, there is no strict data type checking.
No code-reuse: C language doesn’t have OOP features that support source code reusability⁶.

Purpose of C Programming

C is an imperative procedural language, supporting structured programming, lexical variable scope, and recursion, with a static type system. It was designed to be compiled to provide low-level access to memory and language constructs that map efficiently to machine instructions, all with minimal runtime support. Despite its low-level capabilities, the language was designed to encourage cross-platform programming.

Who is C Programming For?

C is a mid-level programming language that provides efficiency and reliability to programmers. Originally the programming language was developed to cater to writing system software. Today C is used to develop firmware and applications. It’s a procedural language that provides low-level access to multiple system memories.