pro eve_next_yyyydoy, thisday, nextday
if n_params() ne 2 then begin
print,''
print,'USAGE: next_yyyydoy, yyyydoy_day, yyyydoy_next'
print,''
print,' next_yyyydoy handles new year boundary and'
print,' corrects for all possible leap years. '
endif
year = thisday/1000l
doy = thisday - (year*1000l)
if doy gt 366 then begin
print,'Day of year greater than 366 is not possible.'
print,'Returning'
return
endif
if doy eq 365 then begin
if ((year mod 400 eq 0) or ((year mod 4 eq 0) and (year mod 100) ne 0)) $
then leap_cor = 1l else leap_cor = 0l
if leap_cor eq 1 then doy = 365 else begin
year = year + 1l
doy = 0
endelse
endif
if doy eq 366 then begin
year = year + 1l
doy = 0
endif
nextday = (year*1000l) + doy + 1l
return
end