class a2
{ 
   public static void main(String args[]) 
    { 
      int N=5; 
      int i=1,j,k,m; 
       for(m=1;m <=2*N-1;m++) 
       { 
         for(j=1;j <=Math.abs(N-i);j++) 
          System.out.print(' '); 
          k=N-Math.abs(N-i); 
         for(j=1;j <=2*k-1;j++) 
          System.out.print('*'); 
          System.out.println(); 
          i++; 
       } 
     } 
} 

public class Test {

    public static void main(String[] args) {
        printDiamond(7, true);
        System.out.println();
        printDiamond(7, false);
    }

    /**
     * 输出菱形
     * @param line       菱形的行数
     * @param isSolid    是否为实心
     */
    private static void printDiamond(int line, boolean isSolid) {
        line = line % 2 == 0 ? line + 1 : line;
        for(int k = line / 2, i = -k; i <= k; i++) {
            for(int j = -k, m = k - Math.abs(i); j <= m; j++) {
                boolean b;
                if(isSolid) {
                    b = Math.abs(j) + Math.abs(i) > k;
                } else {
                    b = Math.abs(j) + Math.abs(i) != k;                    
                }
                System.out.print(b ? " " : "*");
            }
            System.out.println();
        }
    }
}

    j=
    -3  -2  -1   0   1   2   3
i= +---+---+---+---+
-3 |   |   |   | * |
   +---+---+---+---+---+
-2 |   |   | * | * | * |
   +---+---+---+---+---+---+
-1 |   | * | * | * | * | * |
   +---+---+---+---+---+---+---+
 0 | * | * | * | * | * | * | * |
   +---+---+---+---+---+---+---+
 1 |   | * | * | * | * | * |
   +---+---+---+---+---+---+
 2 |   |   | * | * | * |
   +---+---+---+---+---+
 3 |   |   |   | * |
   +---+---+---+---+