C++ Program To Print Hollow Star Pyramid Diamond Shape Pattern

Last Updated : 18 Aug, 2026

A hollow diamond pattern is a star pattern in which only the boundary of the diamond is printed, while the inside is filled with spaces. The pattern is formed by combining an upper and a lower hollow pyramid.

  • The number of rows in the complete diamond is 2n - 1.
  • Nested loops are used to control leading spaces and the hollow space between the boundary stars.

Illustration

For n = 5, the pattern contains 2n - 1 = 9 rows:

*
* *
* *
* *
* *
* *
* *
* *
*

Using for Loop

The upper half is printed first, followed by the lower half. For each row, the program prints leading spaces, a boundary star, the required inner spaces, and another boundary star.

C++ 
#include <iostream>
using namespace std;

int main()
{

    int n = 5, rows, columns;
    // for loop is used to identify the number of rows and
    // it is used to print upper triangle
    for (rows = 1; rows <= n; rows++) {
        // used for printing the spaces
        for (columns = n; columns > rows; columns--) {
            cout << " ";
        }
        // print star
        cout << "*";
        // again print the spaces
        for (columns = 1; columns < (rows - 1) * 2;
             columns++) {
            cout << " ";
        }
        if (rows == 1) {
            cout << "\n";
        }
        else {
            cout << "*\n";
        }
    }
    // for loop is used to identify the number of rows and
    // it is used to print lower triangle
    for (rows = n - 1; rows >= 1; rows--) {
        // used for printing the spaces
        for (columns = n; columns > rows; columns--) {
            cout << " ";
        }
        // print star
        cout << "*";
        for (columns = 1; columns < (rows - 1) * 2;
             columns++) {
            cout << " ";
        }
        if (rows == 1) {
            cout << "\n";
        }
        else {
            cout << "*\n";
        }
    }
    return 0;
}

Output
    *
   * *
  *   *
 *     *
*       *
 *     *
  *   *
   * *
    *

Using while Loop

The same pattern can be generated using while loops. The first part prints the upper half, and the second part prints the lower half.

C++ 
#include <iostream>
using namespace std;

int main()
{

    int n = 5, rows = 1, columns;

    // while loop is used to identify the number of rows and
    // it is used to print upper triangle
    while (rows <= n) {
        columns = n;

        // used for printing the spaces
        while (columns > rows) {
            cout << " ";
            columns--;
        }
        // print star
        cout << "*";
        columns = 1;
        while (columns < (rows - 1) * 2) {
            cout << " ";
            columns++;
        }
        if (rows == 1) {
            cout << "\n";
        }
        else {
            cout << "*\n";
        }
        rows++;
    }
    // while loop is used to identify the number of rows and
    // it is used to print lower triangle
    rows = n - 1;
    while (rows >= 1) {
        columns = n;
        // used for printing the spaces
        while (columns > rows) {
            cout << " ";
            columns--;
        }
        // print star
        cout << "*";
        columns = 1;
        while (columns < (rows - 1) * 2) {
            cout << " ";
            columns++;
        }
        if (rows == 1) {
            cout << "\n";
        }
        else {
            cout << "*\n";
        }
        rows--;
    }
    return 0;
}

Output
    *
   * *
  *   *
 *     *
*       *
 *     *
  *   *
   * *
    *
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