杨辉三角

public class yanghui {  

                      public static void main(String args[]){   

                                int[][] a; 

                                 a=new int [5][5];   

                                  int i,j;  

                                   for(i=0;i<5;i++){    

                                                          for(j=0;j<=i;j++){    

                                                                        if(j==0||j==i)     

                                                                             a[i][j]=1;        

                                                                    else     

                                                                   a[i][j]=a[i-1][j-1]+a[i-1][j];        

                                                                   System.out.print(a[i][j]+"") ;}     

                                                                    System.out.print(" ");   

 }      

 }  

}