#include <math.h>

/***************************************************/	
/* Juliandate returns the JD given integer ID numbers. */
/***************************************************/	

double juliandate( int year, int month, int day)
{
	double y,M,B,JD;

	if (month > 2)  {
		y=  1900.0 + (double) year;
		M = (double) month;
	}
	else {
		y=  1899.0 + (double) year;
		M = (double) month + 12;
	}	
	B=   floor( ( y ) / 400.0) -
		 floor( ( y ) / 100.0); 

 	JD =  floor( 365.25 * y ) + 
		+ floor(30.6001 * ( 1.0 + (double) M )) +
		 B + day + (double) 1720996.5 ;

	return(JD);
}