/* This program creates a perfect checkerboard pattern, regardless of the world's dimensions.
 */

public class CheckerboardKarel extends SuperKarel {


public void run() {
		fillFirstRow();
		while (rightIsClear()) {
			moveToNextRow();
			fillEvenRow();
			if (rightIsClear()); {
				moveToNextRow();
				fillOddRow();
			}
		}
	}
	
	/* fillFirstRow fills every other square with a beeper,
	 * starting with the westernmost square.
	 * Precondition is Karel is on the westernmost square of a row, facing east.
	 * Postcondition is that Karel is on the westernmost square of his row, facing west.
	 */
	
	private void fillFirstRow() {
		putBeeper();
		while (frontIsClear()) {
			move();
			if (frontIsClear()) {
				move();
				putBeeper();
			}
		}
		turnAround();
		while (frontIsClear()) {
			move();
		}
	}
	
	/* moveToNextRow moves Karel up a row.  
	 * Precondition is that he must be in the westernmost square facing west after completing a row.
	 * Postcondition is that he ends up one row up in the westernmost square, facing east.
	 */
	
	private void moveToNextRow() {
		turnRight();
		move();
		turnRight();
	}
	
	/* fillEvenRow fills a beeper on every other corner starting one square east of the westernmost point.
	 * Precondition is Karel is on an even row at the westernmost point, facing east.
	 * Postcondition is Karel is back in the westernmost point, facing west.
	*/
	
	private void fillEvenRow() {
		while (frontIsClear()) {
			move();
			putBeeper();
			if (frontIsClear()) {
				move();
			}
		}
		turnAround();
		while (frontIsClear()) {
			move();
		}
	}
	
	/*fillOddRow fills a beeper on every other corner, starting with the westernmost corner of his row.
	 * Precondition is that he is on the westernmost corner of an odd row, facing east.
	 * Postcondition is that he is on back on the westernmost corner of that row, facing west.
	 */
	
	private void fillOddRow() {
		putBeeper();
		while (frontIsClear()) {
			move();
			if (frontIsClear()) {
				move();
				putBeeper();
			}
		}
		turnAround();
		while (frontIsClear()) {
			move();
		}
		
	}
}

	if (rightIsClear()); {  // <== HERE, remove the ;