;{SelLength = 0}
TmpStr := Copy(Text,1,SelStart-1)+Copy(Text,SelStart+1,255)
else {Key in [''''A''''..''''Z'''', etc]}
TmpStr := Copy(Text,1,SelStart)+Key+Copy(Text,SelLength+SelStart+1,255);
if TmpStr = '''' then Exit;
{ update SelSt to the current insertion point }
if (Key = Chr(vk_Back)) and (SelSt > 0) then Dec(SelSt)
else if Key <> Chr(vk_Back) then Inc(SelSt);
Key := #0; { indicate that key was handled }
if SelSt = 0 then
begin
Text:= '''';
Exit;
end;
{Now that TmpStr is the currently typed string, see if we can locate a match }
Found := False;
for i := 1 to Items.Count do
if Copy(Items[i-1],1,Length(TmpStr)) = TmpStr then
begin
Text := Items[i-1]; { update to the match that was found }
ItemIndex := i-1;
Found := True;
Break;
end;
if Found then { select the untyped end of the string }
begin
SelStart := SelSt;
SelLength := Length(Text)-SelSt;
end
else Beep;
end;
end;
## Copy, Chr, SelStart, SelLength example
-----------------------------------------------------------------------------
High 传回注脚的最大值.
-----------------------------------------------------------------------------
Unit System
函数原型 function High(X);
范例 [Ordinal type]
procedure TForm1.Button1Click(Sender: TObject);
var
Low_S:String;
High_S:string;
S:String;
begin
High_S:='''' High=''''+IntToStr(High(Word));
Low_S:=''''Low=''''+IntToStr(Low(Word));
S:=Low_S+High_S;
Label1.Caption:=S;
end;
S:=Low=0 High=65535
[Array type]
procedure TForm1.Button1Click(Sender: TObject);
var
P : Array[5..21] of Double;
Low_S:String;
High_S:string;
S:String;
begin
High_S:='''' High=''''+IntToStr(High(P));
Low_S:=''''Low=''''+IntToStr(Low(P));
S:=Low_S+High_S;
Label1.Caption:=S;
end;
S:=Low=5 High=21
[String type]
procedure TForm1.Button1Click(Sender: TObject);
var
P : String[23];
Low_S:String;
High_S:string;
S:String;
begin
High_S:='''' High=''''+IntToStr(High(P));
Low_S:=''''Low=''''+IntToStr(Low(P));
S:=Low_S+High_S;
Label1.Caption:=S;
end;
S:=Low=0 Hight=23
P:ShortString;
S:=Low=0 Hight=255
P:String;
长字串不可,会有错误讯号.
[Open array]
function Sum( var X: array of Double): Double;
var
I: Word;
S: Double;
begin
S := 0;
{ Note that open array index range is always zero-based. }
for I := 0 to High(X) do S := S + X[I];
Sum := S;
end;
Example
function Sum( var X: array of Double): Double;
var
I: Word;
S: Real;
begin
S := 0; { Note that open array index range is always zero-based. }
for I := 0 to High(X) do S := S + X[I];
Sum := S;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
List1: array[0..3] of Double;
List2: array[5..17] of Double;
X: Word;
S, TempStr: string;
begin
for X := Low(List1) to High(List1) do
List1[X] := X * 3.4;
for X := Low(List2) to High(List2) do
List2[X] := X * 0.0123;
Str(Sum(List1):4:2, S);
S := ''''Sum of List1: '''' + S + #13#10;
S := S + ''''Sum of List2: '''';
Str(Sum(List2):4:2, TempStr);
S := S + TempStr;
MessageDlg(S, mtInformation, [mbOk], 0);
end;
## Low, High Example
-----------------------------------------------------------------------------
Low 传回注脚的最小值.
-----------------------------------------------------------------------------
Unit System
函数原型 function Low(X);
说明 Ordinal type The lowest value in the range of the type
Array type The lowest value within the range of the
index type of the array
String type Returns 0
Open array Returns 0
String parameter Returns 0
-----------------------------------------------------------------------------
Ord 传回列举型态的数值.
-----------------------------------------------------------------------------
Unit System
函数原型 function Ord(X): Longint;
范例 procedure TForm1.Button1Click(Sender: TObject);
type
Colors = (RED,BLUE,GREEN);
var
S: string;
begin
S := ''''BLUE has an ordinal value of '''' + IntToStr(Ord(RED)) +
#13#10;
S := S+''''The ASCII code for "c" is '''' + IntToStr(Ord(''''c'''')) + ''''
decimal'''';
MessageDlg(S, mtInformation, [mbOk], 0);
end;
-----------------------------------------------------------------------------
Round 将实数转为整数.(有四舍五入)
-----------------------------------------------------------------------------
Unit System
函数原型 function Round(X: Extended): Longint;
范例 var
S, T: string;
begin
Str(1.4:2:1, T);
S := T + '''' rounds to '''' + IntToStr(Round(1.4)) + #13#10;
Str(1.5:2:1, T);
S := S + T + '''' rounds to '''' + IntToStr(Round(1.5)) + #13#10;
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