C programming language

C is multi-paradigm programming language (I started learn it later than needed 😼). By design work efficiently with typical machine instructions.

It’s some like low-level programming language (but C is high-level and general-purpose programming language). It’s support functional/procedure programming paradigm.

C common used in OS development, microcontroller firmware development, databases, game development, utilities, etc.

ANSI C

ANSI C, ISO C, and Standard C are successive standards for the C programming language published by the American National Standards Institute (ANSI) and ISO/IEC JTC 1/SC 22/WG 14 of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Historically, the names referred specifically to the original and best-supported version of the standard (known as C89 or C90). Software developers writing in C are encouraged to conform to the standards, as doing so helps portability between compilers.
— Wikipedia

Latest standard: ANSI C - Wikipedia#C2x

Learning path