java输出九九乘法表

正三角：

public class Chengfabiao {
       public static void main(String[] args){
                   int i, j;
                   for(i=1; i<=9; i++){
                           for(j=1; j<=9; j++){
                                   if(i>=j) {
                                        System.out.printf("%d*%d=%2d  ", j, i, j * i);
                                    }
                                   else{
                                       System.out.print("        ");
                                        }
                               }
                           System.out.print("\n");
                       }
               }
}      

倒三角：

public class Chengfabiao {
       public static void main(String[] args){
                   int i, j;
                   for(i=1; i<=9; i++){
                           for(j=1; j<=9; j++){
                                   if(i<=j) {
                                        System.out.printf("%d*%d=%2d  ", i, j, i * j);
                                    }
                                   else{
                                       System.out.print("        ");
                                        }
                               }
                           System.out.print("\n");
                       }