Question

我是C编程的初学者。这是我的代码。但是我不知道如何解决。这很奇怪。出了点问题。请帮助我修复它！谢谢。

#include <stdio.h>

int main(void)
{
    int num, n, r, c, sp;
    scanf("%d", &num);
    printf("\n");

    n = num;

    for (r = 1; r <= num; r++)
    {
        for (sp = 1; sp < r; sp++)
            printf(" ");

        for (c = 1; c <= n; c++)
            printf("**");
        n--;
        printf("\n");
    }

Answer 1

始终首先绘制整洁的小图片并进行分析：

assume mid_height = 5
           height = 2 * mid_height - 1

               +---------------------------- = 0 ... height - 1
               |        +------------------- = line < mid_height ? line : height - line - 1
               |        |        +---------- = height + 1 - spaces * 2
               |        |        |       +-- = mid_height <= line && line < height - 1
               |        |        |       |
               |    leading   stars/   points
1234567890    line   spaces   points    line  
**********     0        0       10       no
 ********      1        1        8       no
  ******       2        2        6       no
   ****        3        3        4       no
    **         4        4        2       no
   *..*        5        3        4       si
  *....*       6        2        6       si
 *......*      7        1        8       si
**********     8        0       10       no

之后，这只是一个写作练习：

#include <stdio.h>

int main(void)
{
    int mid_height;
    while (printf("Please enter the mid height of the hourglass: "),
           scanf("%d", &mid_height) != 1 || mid_height < 1) {
        fputs("Input error!\n\n", stderr);
        int ch;
        while ((ch = getchar()) != EOF && ch != '\n');
    }
    putchar('\n');

    int height = 2 * mid_height - 1;

    for (int line = 0; line < height; ++line) {
        int spaces = line < mid_height ? line : height - line - 1;
        int points_line = mid_height <= line && line < height - 1;
        for (int w = 0; w < height + 1 - spaces; ++w) {
            int points = points_line && w != spaces && w != height - spaces;
            putchar(w < spaces ? ' ' : points ? '.' : '*');
        }
        putchar('\n');
    }
}

输出：

Please enter the mid height of the hourglass: 5

**********
 ********
  ******
   ****
    **
   *..*
  *....*
 *......*
**********

如何打印移动的沙漏？

1 个答案:

输出：