moon phase

int moon_phase(int y, int m, int d)
{
    /*
      calculates the moon phase (0-7), accurate to 1 segment.
      0 = > new moon.
      4 => full moon.
      */

    int c,e;
    double jd;
    int b;

    if (m < 3) {
        y--;
        m += 12;
    }
    ++m;
    c = 365.25*y;
    e = 30.6*m;
    jd = c+e+d-694039.09;  /* jd is total days elapsed */
    jd /= 29.53;           /* divide by the moon cycle (29.53 days) */
    b = jd;		   /* int(jd) -> b, take integer part of jd */
    jd -= b;		   /* subtract integer part to leave fractional part of original jd */
    b = jd*8 + 0.5;	   /* scale fraction from 0-8 and round by adding 0.5 */
    b = b & 7;		   /* 0 and 8 are the same so turn 8 into 0 */
    return b;
}

int moon_phase(int year,int month,int day)
{
    /*
      calculates the moon phase (0-7), accurate to 1 segment.
      0 = > new moon.
      4 => full moon.
      */
    
    int d = day,g,e;
    if (month == 2) d += 31;
    else if (month > 2) d += 59+(month-3)*30.6+0.5;
    g = (year-1900)%19;
    e = (11*g + 29) % 30;
    if (e == 25 || e == 24) ++e;
    return ((((e + d)*6+5)%177)/22 & 7);
}