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DELPHI常用函数集及简要范例 |
热 ★★★★ |
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DELPHI常用函数集及简要范例 |
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作者：闵涛 文章来源：闵涛的学习笔记 点击数：19880 更新时间：2009/4/23 18:30:33  |
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bsp; else
Msg := Msg + '''' is equal to ''''
Msg := Msg + Edit2.Text;
ShowMessage(Msg);
end;
var
S1,S2: PChar;
I: Integer;
Res: string;
begin
S1:= ''''ABC'''';
S2:= ''''abc'''';
I:= StrIComp(S1, S2); { I := 0, ?.?. S1 = S2 }
if I>0 then Res:= ''''>'''' else
if I<0 then Res:= ''''<'''' else Res:= ''''='''';
MessageDlg( S1 + Res + S2, mtInformation, [mbOk], 0);
end;
-----------------------------------------------------------------------------
StrLCat 字串相加.(指定长)
-----------------------------------------------------------------------------
Unit SysUtils
函数原型 function StrLCat(Dest, Source: PChar; MaxLen: Cardinal):
PChar;
范例 uses SysUtils;
var
S: array[0..13] of Char;
begin
StrLCopy(S, ''''Object'''', SizeOf(S) - 1);
StrLCat(S, '''' '''', SizeOf(S) - 1);
StrLCat(S, ''''Pascal'''', SizeOf(S) - 1);
Canvas.TextOut(10, 10, StrPas(S));
end;
Example
procedure TForm1.Button1Click(Sender: TObject);
var
FirstHalf: PChar;
SecondHalf: PChar;
HalfLen: Integer;
begin
HalfLen := StrLen(PChar(Edit1.Text)) div 2;
GetMem(FirstHalf,HalfLen+2);
GetMem(SecondHalf,HalfLen+2);
FirstHalf^ := Chr(0);
SecondHalf^ := Chr(0);
StrLCat(FirstHalf, PChar(Edit1.Text), HalfLen);
StrCat(SecondHalf, PChar(Edit1.Text) + HalfLen);
Application.MessageBox(FirstHalf, ''''First Half'''', MB_OK);
Application.MessageBox(SecondHalf, ''''Second Half'''', MB_OK);
FreeMem(FirstHalf);
FreeMem(SecondHalf);
end;
const
S1: PChar = ''''???'''';
S2: PChar = ''''?????????'''';
var
S: array[0..13] of Char;
begin
StrLCopy(S, S1, StrLen(S1));
StrLCat(S, S2, 6); { S :=''''??????'''' }
MessageDlg(S, mtInformation, [mbOk], 0);
end;
## StrLen, StrLCat Example
-----------------------------------------------------------------------------
StrLComp 比较两字串大小.(指定长)
-----------------------------------------------------------------------------
Unit SysUtils
函数原型 function StrLComp(Str1, Str2: PChar; MaxLen: Cardinal):
Integer;
范例 uses SysUtils;
const
S1: PChar = ''''Enterprise''''
S2: PChar = ''''Enter''''
var
Result: string;
begin
if StrLComp(S1, S2, 5) = 0 then
Result := ''''equal''''
else
Result := ''''different'''';
Canvas.TextOut(10, 10, ''''The first five characters are '''' +
Result);
end;
example
uses SysUtils;
const
S1: PChar = ''''Enterprise''''
S2: PChar = ''''Enter''''
var
ComStr: string;
begin
if StrLComp(S1, S2, 5) = 0 then
ComStr := ''''equal''''
else
ComStr := ''''different'''';
Canvas.TextOut(10, 10, ''''The first five characters are '''' + ComStr);
end;
const
S1: PChar = ''''?????????'''';
S2: PChar = ''''????????'''';
var
I: Integer;
S: string;
begin
I:= 5;
if StrLComp( S1, S2, I) = 0 then S:= ''''?????'''' else S:= ''''????????'''';
MessageDlg( ''''?????? ''''+ IntToStr(I)+ '''' ???????? ????? ''''+ S, mtInformation,[mbOk], 0);
end;
-----------------------------------------------------------------------------
StrLCopy 拷贝字串.(指定长)
-----------------------------------------------------------------------------
Unit SysUtils
函数原型 function StrLCopy(Dest, Source: PChar; MaxLen:
Cardinal): PChar;
范例 uses SysUtils;
var
S: array[0..11] of Char;
begin
StrLCopy(S, ''''ObjectPascal'''', SizeOf(S) - 1);
Canvas.TextOut(10, 10, StrPas(S));
end;
Example
uses SysUtils;
const MAX_BUFFER = 10;
procedure TForm1.Button1Click(Sender TObject);
var
Buffer: array [0..MAX_BUFFER] of char;
begin
StrLCopy(Buffer, PChar(Edit1.Text), MAX_BUFFER);
Application.MessageBox(Buffer, ''''StrLCopy Example'''', MB_OK);
end;
var
S: PChar;
begin
StrLCopy( S, ''''?????????'''', 5); { S := ''''?????'''' }
...
end;
-----------------------------------------------------------------------------
StrLen 传回字串长度.(不含终止位元)
-----------------------------------------------------------------------------
Unit SysUtils
函数原型 function StrLen(Str: PChar): Cardinal;
范例 uses SysUtils;
const
S: PChar = ''''E Pluribus Unum'''';
begin
Canvas.TextOut(5, 10, ''''The string length of "'''' + StrPas(S)
+ ''''" is '''' + IntToStr(StrLen(S)));
end;
Example
procedure TForm1.Button1Click(Sender: TObject);
var
FirstHalf: PChar;
SecondHalf: PChar;
HalfLen: Integer;
begin
HalfLen := StrLen(PChar(Edit1.Text)) div 2;
GetMem(FirstHalf,HalfLen+2);
GetMem(SecondHalf,HalfLen+2);
FirstHalf^ := Chr(0);
SecondHalf^ := Chr(0);
StrLCat(FirstHalf, PChar(Edit1.Text), HalfLen);
StrCat(SecondHalf, PChar(Edit1.Text) + HalfLen);
Application.MessageBox(FirstHalf, ''''First Half'''', MB_OK);
Application.MessageBox(SecondHalf, ''''Second Half'''', MB_OK);
FreeMem(FirstHalf);
FreeMem(SecondHalf);
end;
const
S: PChar = ''''????? ????? ????? ????????!'''';
begin
MessageDlg( S+ #13#10 + ''''?????????? ???????? = '''' + IntToStr( StrLen( S)), mtInformation, [mbOk], 0);
end;
## StrLen, StrLCat Example
-----------------------------------------------------------------------------
StrLIComp 比较两字串大小.(指定长,不分大小写)
-----------------------------------------------------------------------------
Unit SysUtils
函数原型 function StrLIComp(Str1, Str2: PChar; MaxLen:
Cardinals): Integer;
范例 uses SysUtils;
const
S1: PChar = ''''Enterprise''''
S2: PChar = ''''Enter''''
var
Result: string;
begin
if StrLIComp(S1, S2, 5) = 0 then
Result := ''''equal''''
else
Result := ''''different'''';
Canvas.TextOut(10, 10, '' << 上一页 [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] ... 下一页 >>
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