Thank you very much, you are so cool . I did it after some papers. I'm so happy. Now I understand the feeling of solving a problem by working through it. Thank you many times.
public static void main(String[] args) { int n = 4; for(int i =0; i<n;i++){ for (int j = i; j <n; j++) { //System.out.print(i); System.out.print(" "); } for (int j = 0; j <2*i + 1; j++) { System.out.print("*"); } System.out.println(); } }