Delphi語言學習6-函數參數(2)

5.非強類型參數

function Equal(var Source, Dest; Size: Integer): Boolean;
type
  TBytes = array[0..MaxInt - 1] of Byte;
var
  N : Integer;
begin
  N := 0;
  while (N < Size) and (TBytes(Dest)[N] = TBytes(Source)[N]) do
    Inc(N);
    Equal := N = Size;
end;
//使用方法
//Given the declarations 
type
  TVector = array[1..10] of Integer;
  TPoint = record
    X, Y: Integer;
  end;
var
  Vec1, Vec2: TVector;
  N: Integer;
  P: TPoint;
//調用
Equal(Vec1, Vec2, SizeOf(TVector));      // compare Vec1 to Vec2
Equal(Vec1, Vec2, SizeOf(Integer) * N);  // compare first N elements of Vec1 and Vec2
Equal(Vec1[1], Vec1[6], SizeOf(Integer) * 5);   // compare first 5 to last 5 elements of Vec1
Equal(Vec1[1], P, 4);                    // compare Vec1[1] to P.X and Vec1[2] to P.Y

6.字符串參數

//這樣做是錯的
procedure Check(S: string[20]); // syntax error
//這樣做是對的
type TString20 = string[20];
procedure Check(S: TString20);
//OpenString
procedure Check(S: OpenString);