C Program to Print Hollow Hourglass Pattern

The Hollow Hourglass Pattern is a symmetrical pattern that resembles an hourglass but with hollow spaces inside and only edges having characters. In this article, we will learn how to print the Hollow Hourglass Pattern using a C program.

Program to Print Hollow Hourglass Pattern in C

Output

* * * * * * * * * | 1 2 3 4 5 6 7 8 9 | A B C D E F G H I
 * * | 1 7 | A G
 * * | 1 5 | A E
 * * | 1 3 | A C
 * | 1 | A
 * * | 1 3 | A C
 * * | 1 5 | A E
 * * | 1 7 | A G
* * * * * * * * * | 1 2 3 4 5 6 7 8 9 | A B C D E F G H I

Explanation:

• The outer loop prints each row i.e. 2 * n - 1 rows.
• The l variable determines the relative position of the current row from the top or bottom center:
  • Top half: l = i.
  • Bottom half: l = 2 * n - 2 - i.
• The leading spaces are printed by the first inner loop according to the level
• The top and bottom boundaries are printed by the second inner loop using condition: i == 0 || i == 2 * n - 2
• The condition k == 0 || k == 2 * (n - l) - 2 ensures stars at the boundaries of each row for inner rows.