public class Life1D {

	private Rule rule;
	private int stepCount;

	public static void main (String [ ] args) {
		Life1D simulation = new Life1D ( );
		simulation.processArgs (args);
		simulation.producePBM ( );
	}
	
	// Print, in Portable Bitmap format, the image corresponding to the rule and step count
	// specified on the command line.
	public void producePBM ( ) {
		// You fill this in.
	}
	
	// Retrieve the command-line arguments, and convert them to values for the rule number 
	// and the timestep count.
	private void processArgs (String [ ] args) {
		if (args.length != 2) {
			System.err.println ("Usage:  java Life1D rule# rowcount");
			System.exit (1);
		}
		try {
			rule = new Rule (Integer.parseInt (args[0]));
		} catch (Exception ex) {
			System.err.println ("The first argument must specify a rule number.");
			System.exit (1);
		}
		try {
			stepCount = Integer.parseInt (args[1]);
		} catch (Exception ex) {
			System.err.println ("The second argument must specify the number of lines in the output.");
			System.exit (1);
		}
		if (stepCount < 1) {
			System.err.println ("The number of output lines must be a positive number.");
			System.exit (1);
		}
	}
}

class Rule {

	// Whatever instance variables you need should be declared here.

	public Rule (int ruleNum) {
		// You fill in the code for this constructor.
	}
	
	// Return the output that this rule prescribes for the given input.
	// a, b, and c are each either 1 or 0; 4*a+2*b+c is the input for the rule.
	public int output (int a, int b, int c) {
		// You fill this in.
	}
}