//  Calculation Program for displaying a single egg curve etc.
// (by Mr. Yasuyuki ASAI {Suugaku-Dokusyuu-Juku's]), 30(Thurs.)
// July, 2009



// in the case that a=1, c=2.9



// file name: egg_shaped_curve_SUUDOKU.c



#include< stdio.h>

#include< math.h>



void main(void)

{

	double x,y,a,c,pai;

	double t,dt;

	int i,imax;

	double xx[10001],yy[10001];
// Take care of the upper limit of storage memory capacitance.





	FILE *fp;



// Setting of the constants

	pai=3.1415927;

        a=1;

	c=2.9;
// a circle for c=1, a crecent for 0 < c <1, a round fan
// for 1 < c < 2, and an egg for c > 2



	printf("a=%f\n\n",a);

	 

// Setting of the other parameters

	dt=pai/1000;// plotting interval of the phase angle



// execution of calculation

	i=0;

	for(t=0;t<=2*pai+0.001;t=t+dt)

		{

		i++;



		x=a*((c-2)*cos(t)+c+2)*(cos(t)+1)/4;

		y=a*sin(t);

		yy[i]=y;

		xx[i]=x;

		printf("i=%d,x=%f,y=%f\n",i,x,y);

		}

	imax=i;



// writing the calculated coordinates data of the curve into a textfile

	fp=fopen("egg-shaped curve.txt","w");

	if(fp==NULL)

		{

		printf("FILE OPEN ERROR\n");

		}

	else

		{

		for(i=1;i<=imax;i++)

			{

			fprintf(fp,"%f,%f\n",xx[i],yy[i]);

			}

		fflush(fp);

		fclose(fp);

		}

	printf("end\n");

}// the end of the program