VCL Math Functions: The Ceiling of a Number

	Math Functions: The Ceiling of a Number

Introduction

Consider a floating number such as 12.155. As you can see, this number is between integer 12 and integer 13

In the same way, consider a number such as –24.06. As this number is negative, it is between –24 and –25, with –24 being greater.

In arithmetic, the ceiling of a number is the closest integer that is greater or higher than the number considered. In the first case, the ceiling of 12.155 is 13 because 13 is the closest integer greater than or equal to 12.155. The ceiling of –24.06 is –24.

The ceil() Function

In C++, the function used to obtain the ceiling of a number uses the following syntax:

double ceil(double Value);

The function takes one argument, which is the floating number to be evaluated, and the function returns a double-precision number that is the integer that is greater than or equal to Value. Here is an example:

//---------------------------------------------------------------------------

#include <vcl.h>
#include <math.h>
#pragma hdrstop

#include "Exercise.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TfrmExercice *frmExercice;
//---------------------------------------------------------------------------
__fastcall TfrmExercice::TfrmExercice(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TfrmExercice::btnCeilingClick(TObject *Sender)
{
	double Number  = edtNumber->Text.ToDouble();
	double Ceiling = ceil(Number);

	edtCeiling->Text = UnicodeString(Ceiling);
}
//---------------------------------------------------------------------------

Here is an example of running this code:

Sphere

The Ceil() Function

In the VCL, the function used to get the ceiling of a number is named Ceil and its syntax is:

int __fastcall Ceil(Extended Value);

The Ceil() function takes an argument that represents a long double value. The function returns the greater or equal integer of Value. To use the Ceil() function, include the math.hpp header to your program. Here is an example:

//---------------------------------------------------------------------------

#include <vcl.h>
#include <math.hpp>
#pragma hdrstop

#include "Exercise.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::btnCeilingClick(TObject *Sender)
{
	Extended Number = edtNumber->Text.ToDouble();

	edtCeiling->Text = Ceil(Number);
}
//---------------------------------------------------------------------------

Here is an example of running this code:

Ceiling