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C++Builder3,function ROUND

Posted on 1998-07-28
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Last Modified: 2010-04-02
I want to use the function ROUND which is described in the Help section. I cannot find a headerfile fitting to this function. Who knows how to invoke it?
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Question by:eeks2
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4 Comments
 
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Expert Comment

by:nietod
ID: 1168829
I searched through all the include files in the include directory and its descendant directories and could not find it!  

You might want to look at some of the round functions provided in the SysDefs.h file in the VCL directory.
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Author Comment

by:eeks2
ID: 1168830
The function I am searching for is a function that rounds a double or extended variable to one digit after the decimal point.
like ROUND does, (ROUND(Value,Precision)), whose prototype I cannot find.
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Accepted Solution

by:
nietod earned 100 total points
ID: 1168831
The following should be a good start to writting your own version.  It is not tested by should be close.  I'm not sure it handles negatives in the correct mathematical way (I can't remember the rule.)  It does not check that the precission is valid ( >0).

double RoundToInt(double x)
{
   double RetVal = floor(x);

   if (x -RetVal >= 0.5)
      RetVal = ceil(x);
   return RetVal;
}

double Round(double x,int p)
{
   double m = pow(10,p);
   
   x *= m;
   x = RoundToInt(x);
   x /= m;
   return x;
}
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Author Comment

by:eeks2
ID: 1168832
Works fine even with negative values. Thank You!
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