随笔 - 2146  文章 - 97 评论 - 11767 trackbacks - 253

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{判断字符串中子串个数的函数}
function GetSubStrNum(SubStr,Str: string): Integer;
begin
  Result := 0;
  while Pos(SubStr, Str) > 0 do
  begin
    Str := Copy(Str, Pos(SubStr,Str)+1, Length(Str));
    Inc(Result);
  end;
end;

{测试}
procedure TForm1.FormCreate(Sender: TObject);
var
  s1,s: string;
begin
  s1 := '万一';
  s := '万一万一万一';
  ShowMessage(IntToStr(GetSubStrNum(s1,s))); {3}
end;

end.

再优化:
function GetSubStrNum(const SubStr,Str: WideString): Integer;
var
  pw: PWideChar;
  i,SubLen: Integer;
begin
  Result := 0;
  pw := PWideChar(Str);
  SubLen := Length(SubStr);
  while i > 0 do
  begin
    i := Pos(SubStr, pw);
    Inc(pw, i - 1 + SubLen);
    if Boolean(i) then Inc(Result);
  end;
end;

这是 "道法自然" 兄的代码:
function GetSubStrNum(const SubStr, Str: widestring ): Integer;
var
  i,x: Integer;
  Len,LenSubStr: Integer;
begin
  Result := 0;
  i := 1;
  LenSubStr := Length(SubStr);
  Len := Length(Str) - LenSubStr + 1;
  while i <= Len do
  begin
    if Str[i] = SubStr[1] then
    begin
      x := 1;
      while (x < LenSubStr) and (Str[i+x] = SubStr[x+1]) do Inc(x);
      if (x = LenSubStr) then Result := Result + 1;
      Inc(i,x);
    end else Inc(i);
  end;
end;

posted on 2008-06-09 18:16  万一  阅读(...)  评论(...编辑  收藏