(The C language was introduced in the early 1970s. In 1978, the C language was officially released by Bell Labs of the American Telephone and Telegraph Corporation (ATT). Together B.W.Kernighan and D.M.Ritchit co-authored the famous book "THECPROGRAMMINGLANGUAGE". Generally referred to as "KR", some people call it "KR" specification. However, a complete standard C language is not defined in "KR". Later, the American National Standards Institute formulated a C language standard on this basis, which was released in 1983. Commonly referred to as ANSIC.
C Language Learning and Essence Digest.chm)