﻿ C program of a single heart curve c
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// Calculation Program for displaying a single heart curve III coversed from a Cardioid, 06 Apr., 2010

// file name: heart_curve_c.c

#include< stdio.h>
#include< math.h>

void main(void)
{

double a,pi;// a is the constant of the original Cardioid, pi is the pi
double r,f,df;// the moving radius, the phase angle [radian] and its increment [radian] of a Cardioid after a conversion respectively
double t;// the phase angle [radian] before the conversion
double fmin,fmax;// the minimum and maximum values of the phase angle "f" respectively
double b,c;// coefficients of the conversion from a Cardioid to a heart curve
double d;// the ratio of expansion and contraction in the vertical direction
double p;// newly introduced constant in addition to the previous method II
int i,imax;
double x,y;// coordinates variables obtained likely as in the previous method II
double xx[10001],yy[10001];// coordinates variables after conversion.  // Take care of the upper limit of storage memory capacitance.

FILE *fp;

// setting of the constants
pi=3.14159265;
a=1;

b=1.8;// suitable at between 1.3 and 2.5
c=0.7;// It must be in 0 < c <1 and about 0.5 is suitable.
d=1.2;// suitable at between 0.5 and 1.5
p=0.1;

// setting of the other parameters
fmin=-pi/2;
fmax=3*pi/2;
df=(fmax-fmin)/4000;// plotting interval of the phase angle "f"

// execution of calculation
i=0;
for(f=fmin;f<=fmax;f=f+df)
{
i++;

t=b*sqrt(f+pi/2)-b*sqrt(3*pi/2-f)+(1-b*sqrt(2/pi))*f+b*sqrt(pi/2);
r=a*(1-sin(t));

x=r*(1+c*sin(f))*cos(f);
xx[i]=x;
y=d*r*(1+c*sin(f))*sin(f);

if(x>=0)
{
yy[i]=y+p*x;
}
else
{
yy[i]=y-p*x;
}

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

imax=i;

// writing the calculated coordinates data of the curve into a textfile
fp=fopen("heart_curve_c.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

```

RETURN