使用字符打印椭圆

Question

The general equation for a rotated ellipse centered at (h, k) has the form A(x − h)^2 + B(x − h)(y − k) + C(y − k)^2 = 1, where A and C are positive, and B^2 − 4AC < 0.

I'm trying to print out a filled ellipse using this formula, but it only prints out *s on the first line and \\n's for the next 39 lines, where the loop breaks. I dont get why this is happening.

Here are my lines of code, I'm using the input A=0.04, B=0.001, C=0.01, h and k =6. This should print a 5x10 ellipse, with a center 6, 6.

int x=0, y=0, h, k;
float A, B, C;

printf("input A ");
scanf("%f", &A);
printf("input B ");
scanf("%f", &B);
printf("input C ");
scanf("%f", &C);
printf("input h ");
scanf("%f", &h);
printf("input k ");
scanf("%f", &k);

while(1){
    if(y>=40){
        break;
    }
    if((A*((x-h)*(x-h)))+(B*(x-h)*(y-k))+(C*((y-k)*(y-k)))<=1){
        printf("*");
        x++;
        continue;
    }

    if(x>=80){
        printf("\n");
        y++;
        continue;
    }
    else{
        printf(" ");
        x++;
        continue;
    }
}   
return 0;

Answer 1

This trivial fix-up of your code, converted into an MCVE ( Minimal, Complete, Verifiable Example ), produces the more-or-less elliptical output shown when I run it:

#include <stdio.h>

int main(void)
{
    float A = 0.04;
    float B = 0.001;
    float C = 0.01;
    int h = 6;
    int k = 6;
    int x = 0;
    int y = 0;

    while (y < 40)
    {
        if ((A * (x - h) * (x - h)) +
            (B * (x - h) * (y - k)) +
            (C * (y - k) * (y - k)) <= 1.0)
        {
            printf("*");
            x++;
        }
        else if (x >= 80)
        {
            printf("\n");
            y++;
            x = 0;
        }
        else
        {
            printf(" ");
            x++;
        }
    }
    return 0;
}

Sample output:

$ ./ellipse
   ********     
  *********
  *********
  *********
  *********
  *********
 ***********
  *********
  *********
  *********
  *********
  *********
  ********
   *******
   ******
    *****
      *

(plus a number of blank lines).

^{Since the bulk of the work was done in comments and not by me, I've made this answer Community Wiki.}

Answer 2

This should work too. The factor 'C' is not needed really.

int main()
{
    double A = 20;
    double B = 15;
    double h = 0;//x-offset
    double k = 0; //y-offset

    for (double y = -B - k; y < B; y++)
    {
        for (double x = -A - h; x < A; x++)
        {
            if ((x*x*B*B + y*y*A*A) < A*A*B*B)
                printf("*");
            else
                printf(" ");
        }
        printf("\n");
    }
}