AlternateStreamingCrossingStars

/*
 * Objective:  Print "cross" or "star" pattern from this post:
 *      https://www.facebook.com/groups/java4developers/permalink/1742344979155475/
 * JUnit tests:
 *      https://pastebin.com/pVw3CUY0
 * Additional tests, and tweaked for someone else's implementation:
 *      https://pastebin.com/bZMmLnQs
 */

import java.util.stream.IntStream;

public class AlternateStreamingCrossingStars {

    public static void printCrossingStars(final int n) {

        IntStream.rangeClosed(-n, n).forEach(lineIdx -> {       // For each line...

            IntStream.rangeClosed(1, n).forEach(column -> {     // For each "T" (multiple characters), left to right...
                final String leadingSpacesOrStars = nOf(column, (lineIdx == 0) ? '*' : ' ');    // Spaces -- except for the middle one.
                final char crossBar = (Math.abs(lineIdx) > column) ? ' ' : '*';     // = last character of each "T"
                System.out.print(leadingSpacesOrStars + crossBar);  // = all characters for one "T" (on one line)
            });

            if (n > 0) {    // (special case for zero input -- of no output)
                System.out.println();
            }

        });
    }

    /**
     * @return a <code>String</code> consisting of <code>count</code> copies of the character, <code>chr</code>.
     */
    private static String nOf(final int count, final char chr) {
        return new String(new char[count]).replace('\0', chr);
    }

}