// Calculation Program for calculating shape of a flower with the use of a circle (part A), July 4th, 2012



// file name: flower_curve_A.c



#include< stdio.h>

#include< math.h>



void main(void)

{

	double a,pi;// "a" is the radius of original circle of petal and pi=3.1415...

	double r,z;// "r" and "z"（-π/2 =< z =< π/2）are the moving radius and the phase angle of petal respectively.

	double dz;// increment of "z"

	double f;// the phase angle of petal made of a sharpened original circle

	int n;// numbers of petals

	double alpha;// the sharp angle of the bottom of the petal (The criterion value is "alpha=2*pi/n" in this program.)

	float k;// magnification factor of the criterion angle "alpha=2*pi/n" where 0 < k.

	double zmin,zmax;// the minimum and the maximum values of phase angle "z" respectively

	int i,imax,j;

	float c;// the radius of the center circle

	double xx[30001],yy[30001];// Take care of the upper limit of storage memory capacitance.



	FILE *fp;



// setting of the constants

	pi=3.141592;

	a=1.;



// setting of the other parameters

	printf("Input the numbers of petals. \n n=? ");

	scanf("%d",&n);

	printf("n=%d\n",n);



	alpha=2*pi/n;// the shsarpened angle of the botom of a petal



	printf("Input magnification factor of the criterion angle 'alpha=2*pi/n' where 0 < k. \n k= ? ");

	scanf("%f",&k);

	printf("h=%f\n",k);



	alpha=k*alpha;// the magnificated angle of the botom of the petal



	printf("Input the radius of the center circle. \n c= ? ");

	scanf("%f",&c);

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





	zmin=-pi/2;

	zmax=pi/2;

	dz=(zmax-zmin)/200;// plotting interval of z



// execution of calculation

	i=0;



	for(j=1;j<=n;j++) // sweep of n numbers of petals

	{

		for(z=zmin;z<=zmax+dz;z=z+dz) // sweep of phase angle "z" of the each petal

		{

			i++;



			r=2*a*cos(z);

			

			f=-alpha*z/pi+pi/2-2*pi*(j-1)/n;



			xx[i]=(r+c)*cos(f);

			yy[i]=(r+c)*sin(f);



			printf("i=%d,x=%f,y=%f\n",i,xx[i],yy[i]);

		}

	}

	

	imax=i;



	xx[imax+1]=xx[1];

	yy[imax+1]=yy[1];





// // writing the calculated coordinates data of the curve into a textfile named "flower_curve_A.txt"

	fp=fopen("flower_curve_A.txt","w");

	if(fp==NULL)

		{

		printf("FILE OPEN ERROR\n");

		}

	else

		{

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

			{

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

			}

		fflush(fp);

		fclose(fp);

		}

	printf("end\n");

}// the end of the program