On Sat, May 26, 2007 at 02:15:09PM +0200, Lionel Elie Mamane wrote: > Extract from file string/strtok.c: > > /* Parse S into tokens separated by characters in DELIM. > If S is NULL, the last string strtok() was called with is > used. For example: > char s[] = "-abc-=-def"; > x = strtok(s, "-"); // x = "abc" > x = strtok(NULL, "-="); // x = "def" > x = strtok(NULL, "="); // x = NULL > // s = "abc\0-def\0" > */ > > This, according to my understanding, says that after this code gets > executed, the contents of s is "abc\0-def\0" followed by one > unspecified character (to account for the original length of s, which > is reduced by one in the value given at the end).
> This is wrong. The contents of s after execution of this code is > "-abc\0=-def\0" as running the attached program will demonstrate. You are correct; the final comment should contain your string. > Note that the behaviour described in the comment would imply that > strtok is Θ(strlen(s)^2) (quadratic time, and no less, in the > worst case), because it would in some cases shift the whole string by > one (or more?) positions to the left, which is a linear operation. The only thing strtok() is doing to s is replacing some of the characters with NULs.
