C++ Code Example: diamond pattern

#include <iostream>
using namespace std;

int main() {
    int i, j, rows = 8;

    // upper pyramid
    for (i = 0; i <= rows; i++) {
        for (j = 1; j <= rows - i; j++) {
            cout << ' ';
        }
        for (j = 1; j <= 2 * i - 1; j++) {
            cout << '*';
        }
        cout << "\n";
    }

    // lower pyramid
    for (i = rows - 1; i >= 1; i--) {
        for (j = 1; j <= rows - i; j++) {
            cout << ' ';
        }
        for (j = 1; j <= 2 * i - 1; j++) {
            cout << '*';
        }
        cout << "\n";
    }

    return 0;
}

Output

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