程序代码：

#include <stdio.h>
#include <math.h>
#define MIN(x, y) ((y) < (x) ? (y) : (x))
#define MAX(x, y) ((x) < (y) ? (y) : (x))
#define RAD(x) ((x) * M_PI / 180.0)
#define F1(x) (tan(RAD(162)) * (x) + 1 + cos(RAD(72)))
#define F2(x) (tan(RAD(18)) * (x) + 1 + cos(RAD(72)))
#define F3(x) (tan(RAD(54)) * (x) - sin(RAD(72)) * tan(RAD(54)))
#define F4(x) (tan(RAD(126)) * (x) + 2 + 2 * cos(RAD(72)) \
                + sin(RAD(72)) * tan(RAD(54)))
void draw_star(int scale)
{
    int i, end = rint(scale * sin(RAD(72)) / 2), end2;
    for (i = 0; i <= end; ++i)
    {
        int y1 = rint(F1(i*2.0/scale)*scale),
            y2 = rint(F2(i*2.0/scale)*scale);
        if (y1 != y2)
            printf("%*c%*c\n", y1 + 1, '*', y2 - y1, '*');
        else
            printf("%*c\n", y1 + 1, '*');
    }
    for (i = 0; i < scale; ++i)
        putchar('*');
    end2 = rint(scale * cos(RAD(72)) * 2);
    for (i = 0; i <= end2; ++i)
        putchar(' ');
    for (i = 0; i < scale; ++i)
        putchar('*');
    putchar('\n');
    for (i = end + 1; ; ++i)
    {
        int y1 = rint(F1(i*2.0/scale)*scale),
            y2 = rint(F2(i*2.0/scale)*scale),
            y3 = rint(F3(i*2.0/scale)*scale),
            y4 = rint(F4(i*2.0/scale)*scale);
        if (y4 <= y1 || y3 >= y2)
        {
            printf("%*c%*c\n", y1 + 1, '*', y2 - y1, '*');
            break;
        }
        if (y3 < y4)
        {
            int ymin = MIN(y1, y3);
            printf("%*c%*c\n", ymin + 1, '*', MAX(y2, y4) - ymin, '*');
        }
        else
            printf("%*c%*c%*c%*c\n", y1 + 1, '*', y4 - y1, '*',
                                     y3 - y4, '*', y2 - y3, '*');
    }
}
int main(void)
{
    int scale;
    while (scanf("%d", &scale) == 1)
        draw_star(scale);
    return 0;
}
/* - cc: flags+='-lm' */