Mercurial > cpython-lru_cache-weakref
view Python/atof.c @ 86317:d513149e0c19 2.7
Refer to strftime(3) manpage for platform specific format codes.
Suggested by Skip Montanaro on docs@.
| author | Georg Brandl <georg@python.org> |
|---|---|
| date | Sun, 13 Oct 2013 18:28:25 +0200 |
| parents | fd25030223b0 |
| children |
line wrap: on
line source
/* Just in case you haven't got an atof() around... This one doesn't check for bad syntax or overflow, and is slow and inaccurate. But it's good enough for the occasional string literal... */ #include "pyconfig.h" #include <ctype.h> double atof(char *s) { double a = 0.0; int e = 0; int c; while ((c = *s++) != '\0' && isdigit(c)) { a = a*10.0 + (c - '0'); } if (c == '.') { while ((c = *s++) != '\0' && isdigit(c)) { a = a*10.0 + (c - '0'); e = e-1; } } if (c == 'e' || c == 'E') { int sign = 1; int i = 0; c = *s++; if (c == '+') c = *s++; else if (c == '-') { c = *s++; sign = -1; } while (isdigit(c)) { i = i*10 + (c - '0'); c = *s++; } e += i*sign; } while (e > 0) { a *= 10.0; e--; } while (e < 0) { a *= 0.1; e++; } return a; }
