练习：菱形

 
 
 1                        //上半部分
                for (int m = 1; m <= 10; m++)
                {
                    //输出空格
                    for (int n = 9; n >= m ;n--)
                    {
                        System.out.print(" ");
                    }
                    //输出* 左上
                    for (int n = 1; n <= m; n++)
                    {
                        System.out.print("*");
                    }    
                    
                    //右上
                    for (int n = 1; n < m; n++)
                    {
                        System.out.print("*");
                    }

                    System.out.println();
                }
                
                //下半部分
                for (int m = 1; m <= 9; m++)
                {
                    //输出空格
                    for (int n = 1; n <= m ;n++)
                    {
                        System.out.print(" ");
                    }
                    //输出* 左下
                    for (int n = 9; n >= m; n--)
                    {
                        System.out.print("*");
                    }    
                    
                    //右下
                    for (int n = 9; n > m; n--)
                    {
                        System.out.print("*");
                    }

                    System.out.println();
                }    

输出结果：