// Calculation Program for the volume of an egg body, 30(Mon.) Nov., 2009

// egg equation: (x*x+y*y)**2=a*(x**3)+(a-b)*x*(y**2), The case that a=4 and b=3.2 (or, a=1 and b=0.8) may be the nearest shape to an actual egg.
// The general condition needs b<=a, and in the case of b=0, the curve is led to a circle.

// file name: volume.c

#include< stdio.h>
#include< math.h>

void main(void)
{
	double a,b,v,pi;

// Setting of the constants
	for(;;)
	{
		printf("Input of constant a; a= ? ");
		scanf("%lf",&a);
		if(a>0)
		{
			break;
		}
		else
		{
			printf("Please input the value of a after correcting a as a>0.\n");
		}
	}
	for(;;)
	{
		printf("Input of constant b; b= ? ");
		scanf("%lf",&b);
		if(b>=0&&b<=a)
		{
			break;
		}
		else
		{
			printf("Pleease input the value of b after correcting b as 0< b < a or b=0 or b=a.\n");
		}
	}

	printf("\n");

	pi=3.1415927;

// execution of calculation
	if(b==0)
	{
		v=pi*a*a*a/6;
	}
	else
	{
		v=(pi/2)*((a+b)*(a+b)*(a+b)*a/(6*b)-a*a*a/6-a*a*b/2-((a+b)*(a+b)*(a+b)*(a+b)*(a+b)-(a-b)*(a-b)*(a-b)*(a-b)*(a-b))/(60*b*b));
	}

	printf("The volume of the egg is ; V=%lf\n",v);
	printf("\n");

	printf("end\n");
}// the end of the program