词法分析器用C实现.doc

词法分析器用C实现.doc

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设计界面如上图所示：

代码如下：

namespaceWindowsApplication1

{

publicpartialclassForm1:

Form

{

publicForm1（）

{

InitializeComponent（）;

}

stringStr="",text2="";

privatevoid打开ToolStripMenuItem_Click（objectsender,EventArgse）

{

stringFname="";

openFileDialog1.Filter="文本文件（*.txt）|*.txt";

openFileDialog1.Title="打开文件";

openFileDialog1.RestoreDirectory=true;

if（openFileDialog1.ShowDialog（）==DialogResult.OK）

Fname=openFileDialog1.FileName;

richTextBox1.LoadFile（Fname,RichTextBoxStreamType.PlainText）;

Str=richTextBox1.Text;

}

privatevoid保存ToolStripMenuItem_Click（objectsender,EventArgse）

{

stringFname=openFileDialog1.FileName;

richTextBox1.SaveFile（Fname,RichTextBoxStreamType.PlainText）;

}

privatevoid另存为ToolStripMenuItem_Click（objectsender,EventArgse）

{

stringFname;

saveFileDialog1.Filter="文本文件（*.txt）|*.txt";

saveFileDialog1.Title="保存文件";

saveFileDialog1.RestoreDirectory=true;

saveFileDialog1.ShowDialog（）;

Fname=saveFileDialog1.FileName;

if（Fname!

=""）

richTextBox1.SaveFile（Fname,RichTextBoxStreamType.PlainText）;

}

privatevoid关闭ToolStripMenuItem_Click（objectsender,EventArgse）

{

Application.Exit（）;

}

privatevoid字体ToolStripMenuItem_Click（objectsender,EventArgse）

{

fontDialog1.ShowEffects=true;

fontDialog1.Font=richTextBox1.SelectionFont;

if（fontDialog1.ShowDialog（）==DialogResult.OK）

richTextBox1.SelectionFont=fontDialog1.Font;

}

privatevoid词法分析ToolStripMenuItem_Click（objectsender,EventArgse）

{

Gets.LineNo=1;//初始化行号

Gets.errors=0;//初始化错误个数

Gets.text5="";

stringtext1=richTextBox1.Text+'\0';

Getsgetstring=newGets（）;

text2=getstring.GetString（text1）;

richTextBox2.Text="*****************Token串生成表如下********************"+"\r\n"+text2;

textBox2.Text=getstring.ErrorN0（）;

}

privatevoidForm1_Load（objectsender,EventArgse）

{

}

privatevoid符号表ToolStripMenuItem_Click（objectsender,EventArgse）

{

textBox2.Text="***********************符号表信息******************"+"\r\n";

textBox2.Text+=Gets.text4;

}

privatevoid错误详细信息ToolStripMenuItem_Click（objectsender,EventArgse）

{

textBox2.Text=Gets.text5;

}

}

主要实现功能的代码如下：

创建一个Gets类用来对输入的字符串进行扫描

classGets

{

inti=0,j=0;//记录字符位置,token数组的位置

publicstaticintLineNo=1;//行号

stringtoken="";//记录识别出的单词

stringtext2="";

stringtext3="";//用来记录错误信息

stringwrong="";//记录异常信息

publicstaticinterrors=0;//错误字段的个数

publicstaticstringtext5="";//记录错误的详细信息

intflag1=0,flag2=0,flag3,flag4,flag5,flag6=0;//标记成对出现的界符

publicstaticstringtext4="入口:

单词名称长度类型种属值内存地址"+"\r\n";//用来记录符号表

string[]m_KeyWords=newstring[32]{"auto","double","int","struct","break","else","long","switch","case","enum",

"register","typedef","char","extern","return","union","const","float","short","unsigned","continue","for","signed","void","default",

"goto","sizeof","volatile","do","if","while","static"};

string[]m_operator=newstring[28]{"+","-","*","/","%",">","<",">=","<=","==","-=","+=","*=","/=",//运算符

"!

=","=","%=","&","&&","|","||","!

","++","--","~","<<",">>","?

:

"};

string[]m_bound=newstring[15]{"{","}","[","]",";",",",".","（","）",":

","\"","#",">","<","\'"};//界符

publicstringGetString（stringstr）//读入字符串

{

stringspace="";//空格数

if（str.Length==0）//判断字符串是否为空

return"";

try

{

while（str[i]!

='\0'） //读入字符判断，空格、字母、数字、界符

{

if（str[i]==''||str[i]=='\t'||str[i]=='\r'）

{

i++;//跳过无意义的字符

}