#!/bin/bash
# yeardays
# return the number of days in a year
# usage yeardays yyyy

y=$1

# a year is a leap year if it is even divisible by 4
# but not evenly divisible by 100
# unless it is evenly divisible by 400

# if it is evenly divisible by 400 it must be a leap year
a=`expr $y % 400`
if [ $a -eq 0 ]
then
   echo 366
   exit
fi

#if it is evenly divisible by 100 it must not be a leap year
a=`expr $y % 100`
if [ $a -eq 0 ]
then
   echo 365
   exit
fi

# if it is evenly divisible by 4 it must be a leap year
a=`expr $y % 4`
if [ $a -eq 0 ]
then
   echo 366
   exit
fi

# otherwise it is not a leap year
echo 365