Page 18 and 19 of the second edition of Numerical Recipes in C [1] support your comment. There is also a discussion on the books forum [2] that suggests that all C editions are 1-based and the current C++ editions are 0-based.
This doesn't fit my recollection of having the C edition with a foreword that described how hard and error prone it
was to convert everything from 1-based to 0-based. Maybe my memory plays tricks on me. I'm sure I had the C edition and not the C++ edition and this was before 2000.
My experience with "NR in C" is 2e. There were a number of routines I wanted to run on data stored in native C arrays, so I painstakingly re-wrote the NR functions to use 0-index single dimension C arrays.
