Just to be contrary and throw another wrench or 2 into this interesting discussion, there is also the issue of negative numbers.
e.g. -1.6
Tom's function returns zero
Marian's function returns -1
round(-1.6,0) returns -2
truncate(-1.6,0) returns -1
integer(-1.6) returns -2
e.g. -1.1
Tom's...