parserfm.pas

使用delphi编程语言实现单词解析器

unit ParserFM;

interface

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

type
  TForm1 = class(TForm)
    EdtInput: TEdit;
    BtnAdd: TButton;
    LBWords: TListBox;
    BtnAddWord: TButton;
    BtnDelWord: TButton;
    EdtInputWord: TEdit;
    BtnFindWord: TButton;
    BtnSort: TButton;
    BtnClearAll: TButton;
    Label1: TLabel;
    Label2: TLabel;
    RGSort: TRadioGroup;
    procedure BtnAddClick(Sender: TObject);
    procedure BtnFindWordClick(Sender: TObject);
    procedure BtnAddWordClick(Sender: TObject);
    procedure BtnDelWordClick(Sender: TObject);
    procedure BtnSortClick(Sender: TObject);
    procedure BtnClearAllClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.BtnAddClick(Sender: TObject);
var
  S,T:string;
  InWord: boolean;
  Index,FirstChar:Integer;
begin
  LBWords.Items.Clear;  //先清空列表框里的所有单词
  S:=EdtInput.Text +' ';  //字符串S代表EdtInput里的文本，后面跟一个空格
  InWord:=False;    //是在单词中还是在单词外
  Index:=1;   //Index代表当前读到字符串S的第几个字符了
  FirstChar:=1;  //当前单词的一个字母在S中的索引值
  While Index <= Length(S) do //只要字符串S没结束就继续
  begin
      T:=Copy(S,Index,1);  //读出S的当前字符
      if ( (T>='a') and (T<='z')) or
         ( (T>='A') and (T<='Z')) then     //如果是英文字母
      begin
         if not InWord then FirstChar:=Index;  //如果是一个单词的开始，就让FirstChar:=Index
         InWord:=True;  //现在在单词中
      end
      else if T=' ' then    //如果是空格，表明不在单词中或者单词结束
           begin
              if InWord then  //单词结束
              begin
                  T:=Copy(S,FirstChar,Index-FirstChar); //把单词拷贝出来
                  LBWords.Items.Add(T);    //添加到列表框里
                  InWord:=False;    //不在单词中
              end;
           end
           else    //输入了其它字符，报错，推出循环
               begin
                    ShowMessage('你的输入有误');
                    Break;
               end;
      Inc(Index);   //增加索引值。不可少!否则死循环
  end;  //循环结束
end;

procedure TForm1.BtnFindWordClick(Sender: TObject);
var
    S:string;
    Index:integer;
begin
    S:=Trim(EdtInputWord.Text);
    Index:=LBWords.Items.IndexOf(S);  //在LBWords中寻找一下S，返回索引值
    if Index=-1 then  //未找到
        ShowMessage('未找到 '+S)
    else   //找到
        LBWords.Selected[Index]:=True;  //选择它
end;

procedure TForm1.BtnAddWordClick(Sender: TObject);
var
  S:string;
begin
    S:=Trim(EdtInputWord.Text);
    if IsAWord(S) then
      LBWords.Items.Add(S)
    else
      ShowMessage('输入的单词有误');
end;

procedure TForm1.BtnDelWordClick(Sender: TObject);
begin
    LBWords.Items.Delete(LBWords.ItemIndex);
end;

procedure TForm1.BtnSortClick(Sender: TObject);
begin
    if RGSort.ItemIndex=0 then  //排序
        LBWords.Sorted:=True
    else
        LBWords.Sorted:=False;
end;

procedure TForm1.BtnClearAllClick(Sender: TObject);
begin
    LBWords.Clear;
end;
 //one two three four five six seven eight nine ten
end.