// Calculation Program for displaying a single egg curve 4 (Suugaku-Dokusyuu-Juku's), 07 (Wed.) Oct, 2009



// in the case that a=1, b=0.69, c=0.8



// file name: egg_shaped_curve_SUUDUKU_4.c



#include< stdio.h>

#include< math.h>



void main(void)

{

	double x,y,a,b,c;

	int i,imax,j,m;

	double xmax,dx;

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



	FILE *fp;



// Setting of the constants

        a=1;

	b=0.69;

        c=0.8;



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

	 

// Setting of the other parameters

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

	dx=xmax/2000;// // the plotting interval of x



// execution of calculation

	i=0;

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

		{

		i++;



		xx[i]=x;



		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[i]=y;



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

		}

	imax=i;

	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];

		yy[i]=-yy[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\n",xx[i],yy[i]);

			}

		fflush(fp);

		fclose(fp);

		}

	printf("end\n");

}// the end of the program