Java Programs for Half Floyd number diamond.

package demo;
public class FlodyDiamond
{
 public static void main(String[] args) 
 {
  int n = 4, p = 4, x = 1;
  for (int r = 1; r <= n; r++) {
   for (int c = 1; c <= r; c++, x++) {
    System.out.print(" " + x);
   }
   System.out.println();
  }
  for (int r = n - 1; r > 1; r--, p = p - 2) {
   for (int c = 1, y = p; c <= r; c++, y++) {
    System.out.print(" " + y);
   }
   System.out.println();
  }
  System.out.print(" 1");
  System.out.println();
 }
}

Output:

run:
 1
 2 3
 4 5 6
 7 8 9 10
 4 5 6
 2 3
 1
BUILD SUCCESSFUL (total time: 0 seconds)