java 用“*”打印出菱形

/*打印菱形*/
import java.util.*;
public class HomeWork4_2
{
	public static void main(String[] args)
	{
		System.out.print("Please input the number of lofty's side:");
	    Scanner sc = new Scanner(System.in);
        int l = sc.nextInt();
        int m=0,n=0;
        for(int i=0;i<2*l;i++)
        {
          if(i)
            m++;
          else
            m--;
          for(int j=l-m;j>0;j--)
             System.out.print(" ");
          while(n)
         {
           System.out.print(" *");
           n++;
         }
          n=0;
          System.out.println();
        }
   }
}