因此，我编写了一些代码来显示绘制圆圈。它有点奏效，但以一种非常古怪的方式。这是运行程序并输入6的输出：
O O
O O
O
O
O
O
O
O
O
O O
O O
OOOOOOO
不太好看。
#include <stdio.h>
#include <math.h>
int main()
{
int num, dist, x, y;
printf("Enter the Radius of the Circle: ");
scanf_s("%d", &num);
{
for (x = 1; x <= num * 2; x++)
{
for (y = 1; y <= num * 2; y++)
{
dist = sqrt((x - num) * (x - num) + (y - num) * (y - num));
{
if (dist==num)
{
printf("O");
}
else
{
printf(" ");
}
}
}
printf("\n");
}
}
return 0;
}
这是在网上搜索答案的代码，可能是“换行”代码的位置。尝试过不同的地方，不。
答案 0 :(得分：4)
您的两个for循环应从0开始：
for (x = 0; x <= num * 2; x++)
{
for (y = 0; y <= num * 2; y++)
{
dist = sqrt((x - num) * (x - num) + (y - num) * (y - num));
{
if (dist==num)
{
printf("O");
}
else
{
printf(" ");
}
}
}
printf("\n");
}
您可能缺少第一列和第一行。
答案 1 :(得分：-1)
我写了一次，但是我的布雷森姆算法只使用加法和减法，没有乘法（除了平方以外的乘法）。这是代码。 （您也可以从github获得它）
/* bresenham.c -- program to draw ASCII circles with Bresenham's algorithm.
* Author: Luis Colorado <luicoloradourcola@gmail.com>
* Date: Wed Jan 11 10:50:17 EET 2017
* Disclaimer: (C) 2017 LUIS COLORADO. ALL RIGHTS RESERVED.
* BSD 3-Clause License
*
* Copyright (c) 2017, Luis Colorado
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <errno.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#define FL_FILL (1 << 0)
#define FL_TRACE (1 << 1)
#define F(x) "%s:%d:%s: " x, __FILE__, __LINE__, __func__
/* draws a horizontal line at row y, between x1 and x2 */
static void hline(int x1, int x2, int y)
{
static char theLine[] =
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************"
"*****************************************";
#define THE_LINE_LENGTH (sizeof theLine - 1)
int count = (x2 - x1 + 1) << 1;
printf("\033[%d;%dH", y, x1<<1);
while (count >= THE_LINE_LENGTH) {
fputs(theLine, stdout);
count -= THE_LINE_LENGTH;
} /* while */
printf("%.*s", count, theLine);
} /* hline */
/* draws a dot at coordinates (x, y) */
static void dot(int x, int y)
{
printf("\033[%d;%dH*", y, x<<1);
} /* dot */
/* draws a circle of radius r and center at (cx, cy) */
void bh(int r, int cx, int cy, int flags)
{
int r2 = r*r + r;
int x = 0, x2 = 0, dx2 = 1;
int y = r, y2 = y*y, dy2 = 2*y - 1;
int sum = r2;
while(x <= y) {
if (flags & FL_TRACE) {
printf(F("x=%3d, x2=%5d, dx2=%3d, y=%3d, y2=%5d, dy2=%3d, sum=%5d\n"),
x, x2, dx2, y, y2, dy2, sum);
} else {
if (flags & FL_FILL) {
hline(cx - y, cx + y, cy + x);
if (x) hline(cx - y, cx + y, cy - x);
} else {
dot(cx - y, cy + x); if (y) dot(cx + y, cy + x);
if (x) { dot(cx - y, cy - x); if (y) dot(cx + y, cy - x); }
if (x != y) {
dot(cx - x, cy - y); if (x) dot(cx + x, cy - y);
if (y) { dot(cx - x, cy + y); if (x) dot(cx + x, cy + y); }
}
} /* if */
} /* if */
sum -= dx2;
if (sum <= y2) {
if (!(flags & FL_TRACE) && (flags & FL_FILL) && (x != y)) {
hline(cx - x, cx + x, cy - y);
if (y) hline(cx - x, cx + x, cy + y);
} /* if */
y--; y2 -= dy2; dy2 -= 2;
} /* if */
x++;
x2 += dx2;
dx2 += 2;
} /* while */
} /* bh */
int main(int argc, char **argv)
{
int i;
char *cols = getenv("COLUMNS");
char *lines = getenv("LINES");
int cx, cy;
int opt;
int flags = 0;
while ((opt = getopt(argc, argv, "fv")) != EOF) {
switch(opt) {
case 'f': flags |= FL_FILL; break;
case 'v': flags |= FL_TRACE; break;
} /* switch */
} /* while */
argc -= optind;
argv += optind;
if (cols && lines) {
cx = atoi(cols);
cy = atoi(lines);
} else { /* try to get from tty */
struct winsize win;
int res = ioctl(0, TIOCGWINSZ, &win);
if (res == 0) {
cx = win.ws_col;
cy = win.ws_row;
} else {
fprintf(stderr,
F("TIOCGWINSZ: %s (errno=%d)\n"),
strerror(errno), errno);
cx = 80; cy = 24;
} /* if */
} /* if */
/* center coordinates */
cx /= 4;
cy /= 2;
if (!(flags & FL_TRACE))
fputs("\033[2J", stdout);
for (i = 0; i < argc; i++) {
bh(atoi(argv[i]), cx, cy, flags);
} /* for */
if (!(flags & FL_TRACE)) {
puts("");
fflush(stdout);
} /* if */
} /* main */
它绘制了这样的惊人圆圈：
$ bresenham 5 10
* * * * * * *
* * * *
* *
* *
$ _ * *
* * * * * * *
* * * *
* * * *
* * * *
* * * *
* * * *
* * * *
* * * *
* * * *
* * * *
* * * * * * *
* *
* *
* *
* * * *
* * * * * * *