C

History

C was first described in 1978 by Kernighan and Ritchie in the book "The C Programming Language" (Kernighan and Ritchie 1988). It is now defined by revisions of the ISO/IEC 9899 standard (ISO/IEC 2024) and other technical specifications. The C standards committee is the steward of the C programming language, working with the broader community to maintain and evolve the C language

Basics

Portability

Five kinds of portability issues are enumerated in Annex J of the C standard documents:

• Implementation-defined behavior • Unspecified behavior • Undefined behavior • Locale-specific behavior • Common extensions

(Seacord 2024, 9 chapter.1)

Data Types

Data Type	Signed/Unsigned	Bit Length	Minimum Value	Maximum Value
`char`	Signed	8 bits	-128	127
`unsigned char`	Unsigned	8 bits	0	255
`short`	Signed	16 bits	-32,768	32,767
`unsigned short`	Unsigned	16 bits	0	65,535
`int`	Signed	16 or 32 bits	-2,147,483,648 (32-bit)	2,147,483,647 (32-bit)
`unsigned int`	Unsigned	16 or 32 bits	0	4,294,967,295 (32-bit)
`long`	Signed	32 bits	-2,147,483,648	2,147,483,647
`unsigned long`	Unsigned	32 bits	0	4,294,967,295
`long long`	Signed	64 bits	-9,223,372,036,854,775,808	9,223,372,036,854,775,807
`unsigned long long`	Unsigned	64 bits	0	18,446,744,073,709,551,615
`float`	N/A	32 bits	~ -3.4 x 10³⁸	~ 3.4 x 10³⁸
`double`	N/A	64 bits	~ -1.7 x 10³⁰⁸	~ 1.7 x 10³⁰⁸

References:

Kernighan, Brian W, and Dennis M Ritchie. 1988. The c Programming Language. prentice-Hall.

Seacord, Robert C. 2024. Effective c: An Introduction to Professional c Programming. No Starch Press, Inc.