DiamondCross.java

import java.util.Scanner;

public class DiamondCross {

    /**
    *   Program:    DiamondCross.java
    *   Purpose:    Yahoo! Answers
    *   Creator:    Chris Clarke
    *   Created:    04.01.2014
    */

    public static void main( String args[] ) {

        Scanner scan = new Scanner(System.in);
        System.out.println("Enter value of n: ");
        int n;
        do {
            n=scan.nextInt();
            if (n%2==0) System.out.println("Must be an odd number!");
        } while (n%2==0);

        int sp=20;  // initialise variable sp to the integer value 20

        /*  print upper half of diamond:
            decreasing spaces and increasing stars
        */

        // loop from 1 to 9, increasing by 2 each iteration
        for(int r = 1; r <= n; r += 2) {
            // loop from 1 to the value of sp
            for(int i = 1; i <= sp ; i++)
                // output a space to screen
                System.out.print(" ");

            // loop from 1 to the value of r
            for(int c = 1; c <= r; c++) {
                if (c==1 || c==r/2+1 || c==r || r==n) {
                    // output a star to screen
                    System.out.print("*");
                } else {
                    // output a star to screen
                    System.out.print(" ");
                } // end if
            } // end for
            // output a new line
            System.out.println();
            // the variable sp is decremented by 1
            --sp;
        }//end for r

        /*  print lower half of diamond:
            increasing spaces and decreasing stars
        */

        sp+=2;

        // loop from 7 to 1, decreasing by 2 each iteration
        for(int r = n-2; r >= 1; r -= 2) {
            // loop from 1 to the value of space
            for(int i = 1;i <= sp; i++)
                // output a space to screen
                System.out.print(" ");

            // loop from 1 to the value of r
            for(int c =1;c <= r; c++) {
                if (c==1 || c==r/2+1 || c==r) {
                    // output a star to screen
                    System.out.print("*");
                } else {
                    // output a star to screen
                    System.out.print(" ");
                } // end if
            } // end for
            // output a new line
            System.out.println();
            // the variable space is incremented by 1
            sp++;
        }//end for r
    }//end main()
}//end class