factfunction.java

来自「java写的多功能文件编辑器」· Java 代码 · 共 54 行

/*
 * FactFunction.java - ! operator
 * Copyright (C) 2000 Romain Guy
 * [e-mail]
 * http://www.jext.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either Fact 2
 * of the License, or any later Fact.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.jext.dawn.math;

import org.jext.dawn.*;

/**
 * ! operator<br>
 * Usage:<br>
 * <code>number !</code>
 * @author Romain Guy
 */

public class FactFunction extends Function
{
  public FactFunction()
  {
    super("!");
  }

  public void invoke(DawnParser parser) throws DawnRuntimeException
  {
    int nb = (int) parser.popNumber();
    if (nb >= 0)
    {
      int result = 1;
      for (int i = 1; i <= nb; i++)
        result *= i;
      parser.pushNumber((double) result);
    }
  }
}

// End of FactFunction.java