C programming language/Evolution

The C language evolved fairly continuously from its begining circa 1973 to the first ANSI C standard. K&R is a snapshot from this process. Features that were added between 1973 and K&R:

• struct data type
• long int data type
• unsigned int data type
• =+ (and relatives) had changed to += (and relatives)

Features added after K&R but before the begining of the ANSI C process (IE, these are NOT in K&R):

• void functions
• void * data type
• struct field names in a seperate name space for each struct type
• Assignment operator works for struct data type
• The stdio library and some other standard library functions became available with most implementations (these already existed in at least one implementation at the time of K&R, but were not really standard, so not documented in the book).

Several features were added in the ANSI C standardisation process itself. Most notably, function prototypes (borrowed from C++). Therefore, these were also NOT in K&R.