日期转换成该年的第几周

我看网上多好网友要，这样一个函数，就写下了！

static D_INT8 weekofyear(D_INT16 year,D_INT16 month,D_INT16 day)
{
D_INT8 k = 0;
D_INT8 leap = 0;

time_t t = time( 0 );
char tmp[3];

struct tm newtime, *tm1;
time_t t_of_day;
newtime.tm_sec = 1;
newtime.tm_min = 0;
newtime.tm_hour = 0;
newtime.tm_year = year-1900;
newtime.tm_mon = month-1;
newtime.tm_mday = day;
newtime.tm_isdst = 0;
t_of_day = mktime(&newtime);
tm1 = localtime(&t_of_day);
strftime( tmp, 3, "%U", tm1);
printf("the day the is %sor%d-%d/n", tmp,tmp[0],tmp[1]);
return atoi(tmp);
}