History of C Programming

• The C Programming Language was created by Dennis Ritchie and Ken Thompson at AT&T Bell Labs.
• It was influenced by BCPL (Basic Combined Programming Language).
• In 1965, the development of the Multics operating system started.
• Due to various reasons, this development was halted in 1969.
• Later, Dennis Ritchie joined AT&T Bell Labs and resumed the creation of an operating system, leading to the development of Unix.
• Initially, the Unix operating system was written in Assembly Language.
• To overcome the difficulties of Assembly Language, Dennis Ritchie created C Programming in 1972.
• Initially, C was considered a system programming language, but it later evolved into a general-purpose programming language.

Standardization of C Programming

The C Programming Language was standardized by multiple organizations:

1. K & R Standard (Kernighan & Ritchie Standard) – 1978
2. ANSI Standard (American National Standards Institute) – 1983 (C89)
3. ISO Standard (International Organization for Standardization) – 1990 (C90)
4. C99 Standard – 1999

C Programming Language is supported by various standardization teams, ensuring consistency and portability.

Features (Characteristics) of C Programming

1. General Purpose Programming Language – C can be used to write any kind of software application.
2. Procedural Programming – C supports procedural programming through the use of functions.
3. Block Structured – Code in C is organized within blocks defined by curly brackets {}.
4. Compiled – C is a compiled language, which means the code is translated into machine code by a compiler.
5. Free Flow – C allows the flow of control to be transferred from one point to another.
6. Statically Typed – C requires explicit declaration of data types.
7. Native – C interacts directly with the operating system.
8. Standardized – C has been standardized by multiple organizations (K&R, ANSI, ISO, C99).

Basic Structure of a C Program

Explanation of the Above Program

1. # is a preprocessor directive symbol.
2. #include is used to include the necessary header files. stdio.h is the header file that contains functions for standard input-output operations.
3. int indicates the return type of the main function.
4. main is the name of the entry point function where the execution of the program begins.
5. The function block is enclosed in curly brackets {}.
6. printf is the function responsible for displaying data on the screen.
7. \n is used to insert a new line on the screen.
8. A semicolon ; at the end of a line is mandatory to indicate the end of that statement.
9. The data within double quotes "" is considered a string to be displayed on the screen.
10. return 0 at the end of the main function indicates the successful execution of the program, returning 0 to the operating system.