Question

How to define a petabyte constant in Pascal

Answer 1

program PetabyteConstantExample;

{
  In Free Pascal, the largest unsigned integer type is QWord (64‑bit).
  A petabyte fits comfortably inside 64 bits:

    1 PiB = 2^50  = 1,125,899,906,842,624 bytes
    1 PB  = 10^15 = 1,000,000,000,000,000 bytes
}

const
  // Binary petabyte (pebibyte), using a bit shift.
  // 1 shl 50 = 2^50 bytes.
  PETABYTE_PIB: QWord = QWord(1) shl 50;

  // Decimal petabyte (SI petabyte), using a plain numeric literal.
  // No digit separators, for maximum compatibility.
  PETABYTE_PB: QWord = 1000000000000000;

var
  sizeBinary: QWord;
  sizeDecimal: QWord;

begin
  sizeBinary := PETABYTE_PIB;
  sizeDecimal := PETABYTE_PB;

  WriteLn('1 PiB = ', sizeBinary, ' bytes');
  WriteLn('1 PB  = ', sizeDecimal, ' bytes');
end.



(* 
run:

1 PiB = 1125899906842624 bytes
1 PB  = 1000000000000000 bytes

*)

 

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