Delphi 新语法介绍之运算符重载

技术交流,DH讲解

运算符重载一直是个争议的话题,.其实运算符重载就是方便我们而已,不用不会死人,用了方便点儿而已.D7之后的版本也支持运算符重载.我们来看个例子:
如果我们想2个结构体可以相加,比如说 a,b:TPoint;C:=a+b;是吧,多美好的事情呀.

---

THuangJacky = record
	A,B,C:Integer;
	//+
	class operator Add(a, b: THuangJacky): THuangJacky;
	//=
	class operator Equal(a,b: THuangJacky):Boolean;
end;
var
	Form1: TForm1;
implementation
{$R *.dfm}
{ TH }
class operator THuangJacky.Add(a, b: THuangJacky): THuangJacky;
begin
	Result.A:=a.A + a.A;
	Result.B:=a.B + b.B;
	Result.C:=a.C + b.C;
end;
class operator THuangJacky.Equal(a, b: THuangJacky): Boolean;
begin
	if (a.A=b.A)and(a.B=b.B)and(a.C=b.C) then
		Result:=True
	else
		Result:=False;
end;
procedure TForm1.btn1Click(Sender: TObject);
var
	a,b,c:THuangJacky;
begin
	a.A:=5;a.B:=6;a.C:=7;
	b.A:=2;b.B:=3;b.C:=4;
	//这就是好处
	c:=a+b;
	ShowMessageFmt('%D,%D,%D',[c.A,c.B,c.C]);
	if not (a=b) then
		ShowMessage('not equal');
end;

我们这里的结构体就可以直接+ 和 = 判断了,方便了那些搞算法的人.哈哈.下面附上所有的运算符:

---

Implicit	Conversion	Implicit(a : type) : resultType; (封箱)	implicit typecast
Explicit	Conversion	Explicit(a: type) : resultType; (拆箱)	explicit typecast
Negative	Unary	Negative(a: type) : resultType;	-
Positive	Unary	Positive(a: type): resultType;	+
Inc	Unary	Inc(a: type) : resultType;	Inc
Dec	Unary	Dec(a: type): resultType	Dec
LogicalNot	Unary	LogicalNot(a: type): resultType;	not
BitwiseNot	Unary	BitwiseNot(a: type): resultType;	not
Trunc	Unary	Trunc(a: type): resultType;	Trunc
Round	Unary	Round(a: type): resultType;	Round
Equal	Comparison	Equal(a: type; b: type) : Boolean;	=
NotEqual	Comparison	NotEqual(a: type; b: type): Boolean;	<>
GreaterThan	Comparison	GreaterThan(a: type; b: type) Boolean;	>
GreaterThanOrEqual	Comparison	GreaterThanOrEqual(a: type; b: type): resultType;	>=
LessThan	Comparison	LessThan(a: type; b: type): resultType;	<
LessThanOrEqual	Comparison	LessThanOrEqual(a: type; b: type): resultType;	<=
Add	Binary	Add(a: type; b: type): resultType;	+
Subtract	Binary	Subtract(a: type; b: type) : resultType;	-
Multiply	Binary	Multiply(a: type; b: type) : resultType;	*
Divide	Binary	Divide(a: type; b: type) : resultType;	/
IntDivide	Binary	IntDivide(a: type; b: type): resultType;	div
Modulus	Binary	Modulus(a: type; b: type): resultType;	mod
LeftShift	Binary	LeftShift(a: type; b: type): resultType;	shl
RightShift	Binary	RightShift(a: type; b: type): resultType;	shr
LogicalAnd	Binary	LogicalAnd(a: type; b: type): resultType;	and
LogicalOr	Binary	LogicalOr(a: type; b: type): resultType;	or
LogicalXor	Binary	LogicalXor(a: type; b: type): resultType;	xor
BitwiseAnd	Binary	BitwiseAnd(a: type; b: type): resultType;	and
BitwiseOr	Binary	BitwiseOr(a: type; b: type): resultType;	or
BitwiseXor	Binary	BitwiseXor(a: type; b: type): resultType;	xor

我是DH,今天就说到这里.