// Calculation Program for displaying five egg curves 2-3 (Suugaku-Dokusyuu-Juku's),
// 07 (Wed.) Oct., 2009



// file name:  egg_shaped_curve_4b.c



#include< stdio.h>

#include< math.h>



void main(void)

{

	double x,y,a,b,c,dc,cmax,cmin;

	int i,imax,n,nmax,j,m;

	double xmax,dx;

	double xx[2005],yy[10][1005];
// Take care of the upper limit of storage memory capacitance.



	FILE *fp;



// Setting of the constants

        a=1;

	b=0.69;	

	c=0.8;

	 

// Setting of the other parameters

	xmax=2*a;// the maximum value of x

	dx=xmax/250;// the plotting interval of x



	dc=c/8;

	cmax=c+2*dc+0.00001;

	cmin=c-2*dc;



	i=0;



// execution of calculation

	for(x=0;x<=xmax+dx/10;x=x+dx)

		{

		i++;

		n=0;

		xx[i]=x;



		for(c=cmin;c<=cmax;c=c+dc)

			{

			n++;



			if(x>xmax)

			{

				y=0;

			}

			else

			{

				if(x>c)

				{

			y=b*sqrt(1-((x-c)/(c+2*(a-c)))*((x-c)/(c+2*(a-c))));

				}

				else

				{

					if(x< c)

					{

					y=b*sqrt(1-((x-c)/c)*((x-c)/c));

					}

					else

					{

y=b*sqrt(1-((x-c)/(c+2*(a-c)/2))*((x-c)/(c+2*(a-c)/2)));

					}

				}

			}



			yy[n][i]=y;



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

			}

		}

	imax=i;



	nmax=n;

	j=0;



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

	for(i=imax+1;i<=2*imax;i++)

		{

		j++;

		m=imax-j;



		xx[i]=xx[m];



		for(n=1;n<=nmax;++n)

			{

			yy[n][i]=-yy[n][m];

			}

		}



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

	if(fp==NULL)

		{

		printf("FILE OPEN ERROR\n");

		}

	else

		{

		for(i=1;i<2*imax;i++)

			{

fprintf(fp,"%f,%f,%f,%f,%f,%f\n",
xx[i],yy[1][i],yy[2][i],yy[3][i],yy[4][i],yy[5][i]);

			}

		fflush(fp);

		fclose(fp);

		}

	printf("end\n");

}// the end of the program