How to print x pattern in Java using for loops?

Question

My goal is to get this output when input is 3:

  *     *
   *   *
    * *
     *
    * *
   *   *
  *     *

Here is my code:

public static void PrintX (int number) {
 for (int i = 0; i <= (number * 2 + 1); i++)
   {
       for (int j = 0; j <= (number * 2 + 1); j++)
       {
           if (i == j) 
           {
               System.out.print("*");
           }
           else if (i + j == (number * 2 + 2))
           {
               System.out.print("*");
           }
           else
           {
               System.out.print(" ");
           }
       }
       System.out.println("");
   }
} 

My output when input is 3 is like this and I'm not sure why there is the extra star at the top.

*
 *     *
  *   *
   * *
    *
   * *
  *   *
 *     *

Answer 1

Your outer loop would work as you expect if you set an initial i value of 1. However, you could also make this a little shorter. First, consider storing the number * 2 + 1. Then you might combine a few lambda expressions with IntStream. Basically, you want to map each possible index to a " " or a "*" - so

public static void PrintX(int number) {
    int len = number * 2 + 1;
    IntStream.rangeClosed(1, len).forEachOrdered(i -> {
        IntStream.rangeClosed(0, len)
                .mapToObj(j -> i == j || i + j == len + 1 ? "*" : " ")
                .forEachOrdered(System.out::print);
        System.out.println();
    });
}