Smallest large system simulator

Yves-Marie Morgan

Judges' comments:

To build:

make morgan1

To run:

echo "2013/10/03" | ./morgan1


echo "1985/10/28" | ./morgan1

echo "1996/12/31" | ./morgan1

Try pressing the arrow keys when your focus is in the window.

Selected Judges Remarks:

To verify the output, try echoing the date of an evening with a clear sky. Use binoculars and/or telescope as needed. In some cases you may need to wait for a better time of the evening. In a few cases, such as the South Pole in the summer, you may need to move to a different observing site.

Author’s comments:


It displays the position of the 8 planets of the solar system around the sun. The date given in the command line is in the format YYYY/MM/DD (year, month and day). The direction keys can be used to move in time : Left : go back 1 day. Right : go forward 1 day. Down : go back 20 days. Up : go forward 20 days.

It handles correctly all leap years and the switch between julian calendar and gregorian calendar (10 days missing between 1582/10/04 and 1582/10/15).

The scale is logarithmic to be able to display the 8 planets without having Mercury, Venus, Earth and Mars squizzed around the sun.

The size is not proportinal either.


It also displays the position of 2 famous comets during their last approach : - The first one arround the third IOCCC. - The second one between the thirteenth and fourteenth IOCCC.



Compilation warnings

with gcc 4.7.2 on Linux Ubuntu 12.10 : * prog.c:38:3: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] * prog.c:40:34: warning: value computed is not used [-Wunused-value] * prog.c:56:6: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] * prog.c:58:50: warning: value computed is not used [-Wunused-value] * prog.c:61:5: warning: suggest parentheses around ‘-’ inside ‘>>’ [-Wparentheses]

with clang 3.1 on Linux Ubuntu 12.10 : * prog.c:38:49: warning: ‘&&’ within ‘||’ [-Wlogical-op-parentheses] * prog.c:38:27: warning: ‘&&’ within ‘||’ [-Wlogical-op-parentheses] * prog.c:55:13: warning: ‘&&’ within ‘||’ [-Wlogical-op-parentheses] * prog.c:56:14: warning: ‘&&’ within ‘||’ [-Wlogical-op-parentheses]

Due to most parentheses and braces removed when unecessary.

To verify the display, you can look at one of this programs : * xephem : * homeplanet : *

Creative Commons License

© Copyright 1984-2015, Leo Broukhis, Simon Cooper, Landon Curt Noll - All rights reserved
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.