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Array Size (ARRAYSIZE macro)
Array Size (ARRAYSIZE macro)

Description

This article describes how to get the size of each dimension of a multidimensional array with the ARRAYSIZE macro.
This macro is defined in the "Pascal open array parameter support" file (...\Include\Vcl\SYSOPEN.H) as follows:

#define ARRAYSIZE(a) (sizeof(a)/sizeof(a[0]))

This project contains a form and a TButton: TButton1.

ArraySize.cpp

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"


TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------


void __fastcall TForm1::Button1Click(TObject *Sender)
{
    //Two-dimensional arrays
    double Array2D[1000][110];

    ShowMessage(     "DIM1 =" + String( ARRAYSIZE(Array2D) )
                 + "\nDIM2 =" + String( ARRAYSIZE(Array2D[0]) ) );
    //-------------------------------------------------------------

    //Three-dimensional arrays
    float Array3D[2][3][4];

    ShowMessage(     "DIM1 =" + String( ARRAYSIZE(Array3D) )
                 + "\nDIM2 =" + String( ARRAYSIZE(Array3D[0]) )
                 + "\nDIM3 =" + String( ARRAYSIZE(Array3D[0][0]) ) );

    //Set the array elements to zero:
    for ( int x=0; x< ARRAYSIZE(Array3D); x++ )
        for ( int y=0; y< ARRAYSIZE(Array3D[0]); y++ )
            for ( int z=0; z< ARRAYSIZE(Array3D[0][0]); z++ )
                Array3D[x][y][z] = 0;

    String S;
    //Display the array elements:
    for ( int x=0; x< ARRAYSIZE(Array3D); x++ )
        for ( int y=0; y<  ARRAYSIZE(Array3D[0]); y++ )
            for ( int z=0; z<  ARRAYSIZE(Array3D[0][0]); z++ )
            {
                S +=  "Array3D["
                      + String(x) + "]["
                      + String(y) + "]["
                      + String(z) + "]= "
                      + String( Array3D[x][y][z] ) + " ";
            }

    ShowMessage( S );
    //-------------------------------------------------------------
    
    //Four-dimensional arrays
    float Array4D[10][11][16][2];

    ShowMessage(     "DIM1 =" + String( ARRAYSIZE(Array4D) )
                 + "\nDIM2 =" + String( ARRAYSIZE(Array4D[0]) )
                 + "\nDIM3 =" + String( ARRAYSIZE(Array4D[0][0]) )
                 + "\nDIM4 =" + String( ARRAYSIZE(Array4D[0][0][0]) ) );
}

ArraySize.h

#ifndef Unit1H
#define Unit1H
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:	// IDE-managed Components
        TButton *Button1;
        void __fastcall Button1Click(TObject *Sender);
private:	// User declarations
public:		// User declarations
        __fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif

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