// Calculation Program for displaying four spacies of egg-shaped-curves (Itou's) simultaneousely, 28(Fri.) Mar., 2008

// in the case that a=0.5, b=0.11～0.5

// file name: C_program_2_E.c



#include< stdio.h>

#include< math.h>



void main(void)

{

	double x,y,a,b,db,bmax,pi;

	double t,dt;

	int i,imax,n,nmax;

	double xx[10001],yy[10][10001];// Take care of the upper limit of storage memory capacitance.



	FILE *fp;



// setting of the constants

        pi=3.1415927;

        a=.5;

	bmax=a;

	db=0.13;// selected interval of parameter b



// setting of the other parameters

	dt=pi/1000;// plotting interval of t



	i=0;



// execution of calculation

	for(t=-pi;t<=pi;t=t+dt)

	{

		i++;

		n=0;



		for(b=bmax-3*db;b<=bmax+0.01;b=b+db)

		{

			n++;



			x=a*cos(t);

			y=b*cos(t/4)*sin(t);

			xx[i]=x;

			yy[n][i]=y;



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

		}

	}



	imax=i;

	nmax=n;



// writing the calculated coordinates data of the curves 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,%f,%f,%f\n",xx[i],yy[1][i],yy[2][i],yy[3][i],yy[4][i]);

		}



		fflush(fp);

		fclose(fp);

	}



	printf("end\n");

}// the end of the program