In 1978, Brian Kernighan and Dennis Ritchie published the first edition of The C Programming Language. This book, known to C programmers as
"K&R", served for many years as an informal specification of the language. The version of C that it describes is commonly referred to as K&R
C.
The K&R function definition syntax introduced in the book was later deprecated in the ANSI C and ISO C standards. Even though the K&R
syntax is still supported in the ISO C11 standard, it’s not in ISO C++ standard versions and is not considered readable by most C/C++ developers
today.
Noncompliant code example
int foo(a, b) // Noncompliant K&R C syntax
int a;
char* b;
{
}
Compliant solution
int foo(int a, char* b) { // Compliant
}