journey.java

Java 入门书的源码

//Copyright (c) 1998, Arthur Gittleman
//This example is provided WITHOUT ANY WARRANTY either expressed or implied.

/* Use a recursive method, travel, to journey from start
 * to finish, printing messages to show its progress.
 */

public class Journey {
  private static String indent = "";
  public static void takeOneStep(int step) {
    System.out.println(indent + "Taking step " + step);
  }
  public static void travel(int start, int finish) {
    String oldIndent = indent;
    System.out.println(indent + "Starting travel from " + start + " to " + finish);
    if (start < finish) {
      takeOneStep(start);
      indent += "   "; 
      travel(start+1,finish);
      indent = oldIndent;
    }
    System.out.println(indent + "Finishing travel from " + start + " to " + finish);
  }
  public static void main(String [] args) {
    int start = Integer.parseInt(args[0]);
    int finish = Integer.parseInt(args[1]);
    travel(start,finish);
  }
}