1. conversion of moon_age.c
Hi to all,
I just converted a C function to Euphoria, that can be usefull for people=
making calendar programs, planners etc. It is called 'moon_age' and
calculates the phases of the moon on any day in the future and the past.
I was searching for a method to determine on which day Easter will be in
years to come. In our western (christian) society Easter Sunday is always=
the first sunday after the first full moon in Spring. And this routine ca=
n
calculate the days of full moon, as well as new moon, first quarter etc.
It is also an interesting example of how C code can be translated to bett=
er
readable Euphoria code. There is only one question I have: if you look at=
the last printf in de C code, the expression (phase + 2) * 16 / 59. If yo=
u
know that phase can have values from 0 to 29, this expression (floored)
ranges from 0 to 8. This can never be, since the sequence 'description'
only has got 8 values. In C these are 0 to 7, and in Euphoria 1 to 8. Can=
someone provide me with a better solution?
Further comments are also welcome.
Sincerely,
Ad Rienks
email Ad_Rienks at compuserve.com
writing at 23:07 , =
on maandag 6 oktober 1997
Using EMail Assist for WinCIM
----This is the program moon_age.c ----
/* PD by Michelangelo Jones, 1:1/124. */
/*
** Returns 0 for new moon, 15 for full moon,
** 29 for the day before new, and so forth.
*/
/*
** This routine sometimes gets "off" by a few days,
** but is self-correcting.
*/
int moon_age(int month, int day, int year)
{
static short int ages[] =3D
{18, 0, 11, 22, 3, 14, 25, 6, 17,
28, 9, 20, 1, 12, 23, 4, 15, 26, 7};
static short int offsets[] =3D
{-1, 1, 0, 1, 2, 3, 4, 5, 7, 7, 9, 9};
if (day =3D=3D 31)
day =3D 1;
return ((ages[(year + 1) % 19] + ((day + offsets[month-1]) % 30) +
(year < 1900)) % 30);
}
#ifdef TEST
#include <stdio.h>
#include <stdlib.h>
static char *description[] =3D {
"new", /* totally dark */
"waxing crescent", /* increasing to full & quarter light */
"in its first quarter", /* increasing to full & half light */
"waxing gibbous", /* increasing to full & > than half */
"full", /* fully lighted */
"waning gibbous", /* decreasing from full & > than half */
"in its last quarter", /* decreasing from full & half light */
"waning crescent" /* decreasing from full & quarter light */
};
static char *months[] =3D {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
int main(int argc, char *argv[])
{
int month, day, year, phase;
if (4 > argc)
{
puts("Usage: MOON_AGE month day year");
return EXIT_FAILURE;
}
month =3D atoi(argv[1]);
day =3D atoi(argv[2]);
year =3D atoi(argv[3]);
if (100 > year)
year +=3D 1900;
printf("moon_age(%d, %d, %d) returned %d\n", month, day, year,
phase =3D moon_age(month, day, year));
printf("Moon phase on %d %s %d is %s\n", day, months[month - 1],
year,
description[(int)((phase + 2) * 16L / 59L)]);
}
#endif /* TEST */
---- And this is the EUPHORIA moon_age.ex program ------
/* PD by Michelangelo Jones, 1:1/124. */
--
--/*
--** Returns 0 for new moon, 15 for full moon,
--** 29 for the day before new, and so forth.
--*/
--
--/*
--** This routine sometimes gets "off" by a few days,
--** but is self-correcting.
--*/
include get.e
function moon_age(integer month, integer day, integer year)
integer result
sequence ages, offsets
ages =3D {18, 0, 11, 22, 3, 14, 25, 6, 17,
28, 9, 20, 1, 12, 23, 4, 15, 26, 7}
offsets =3D {-1, 1, 0, 1, 2, 3, 4, 5, 7, 7, 9, 9}
if day =3D 31 then
day =3D 1
end if
result =3D ages[remainder(year + 1, 19) + 1]
result =3D result + remainder(day + offsets[month], 30)
result =3D result + (year < 1900)
result =3D remainder(result, 30)
return result
end function -- moon_age
function input(sequence prompt)
object nummer
puts(1, prompt)
nummer =3D get(0)
nummer =3D nummer[2]
return nummer
end function -- input
constant description =3D {
"new", --/* totally dark *=
;
"waxing crescent", --/* increasing to full & quarter light *=
;
"in its first quarter", --/* increasing to full & half light *=
;
"waxing gibbous", --/* increasing to full & > than half *=
;
"full", --/* fully lighted *=
;
"waning gibbous", --/* decreasing from full & > than half *=
;
"in its last quarter", --/* decreasing from full & half light *=
;
"waning crescent" --/* decreasing from full & quarter light *=
;
}
constant months =3D {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}
integer day, month, year, phase
while 1 do =
clear_screen()
month =3D input("Month: ")
if month =3D 0 then
exit
end if
day =3D input("\nDay: ")
year =3D input("\nYear: ")
if 100 > year then
year =3D year + 1900
end if
phase =3D moon_age(month, day, year)
printf(1, "\nmoon_age(%d, %d, %d) returned %d\n", {month, day, year,
phase})
phase =3D floor((phase + 2) * 16 / 59) + 1
if phase > 8 then
phase =3D 8
end if
printf(1, "Moon phase on %d %s %d is %s\n", {day, months[month], year=
,
description[phase]})
while get_key() =3D -1 do =
end while
end while
