ceil.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

// 
//  Visopsys
//  Copyright (C) 1998-2007 J. Andrew McLaughlin
//  
//  This library is free software; you can redistribute it and/or modify it
//  under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation; either version 2.1 of the License, or (at
//  your option) any later version.
//
//  This library 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 Lesser
//  General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public License
//  along with this library; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//  ceil.c
//

// This is the standard "ceil" function, as found in standard C libraries

#include <math.h>


double ceil(double d)
{
  // The ceil() function computes the smallest integral value not
  // less than x.

  int c = (int) d;
    
  if (d > 0)
    d = (double) (c + 1);

  else if (d < 0)
    // ??? what to do ???  Is ceil(-5.5) == -6.0, or is
    // ceil(-5.5) == -5.0?  -5.0 according to the description.
    d = (double) c;

  return (d);
}