词法分析器(C#实现).doc

精品文档/* * 写在最前面 * 词法分析前先将源码预处理，去掉多余的空格和换行以及注释 * 单词与单词之间最好用空格隔开，否则将被识别为未知符号 * */using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Collections;using System.Text;using System.Windows.Forms;using System.IO;namespace 词法分析 public partial class Form1 : Form private static string 保留字 =bool,break,case,char,do,double,else, false,float,for,if,int,long,main,new,null,private,protected,public, static,true,try,typeof,unit,void,while,return,short,sizeof,switch ; private static string 运算符 =*,/,%,+,-,=, =,!=,&,|,&,|,?:,+=,-=,*=,/=,%=,&=,|=,=, =,=; private static string 界符 = , ;, ., , (, ), :, , , , , / ; private static string 标识符; private static string 常数; private static string 未知符号; private ArrayList temp = new ArrayList(); public Form1() InitializeComponent(); public int Search_Location(string str, string a) /查找字符编码 for (int i = 0; i a.Length; i+) if (str = ai) return i + 1; return -1; public int InsertId(string strr, ref string a)/标识符插入标识符表返回位置 temp.Clear(); if (a = null) temp.Add(strr); else for (int i = 0; i a.Length; i+) if (strr = ai) return i; for (int j = 0; j a.Length; j+) temp.Add(aj); temp.Add(strr); a = (string)temp.ToArray(typeof(string); return a.Length - 1; private string Pretreatment() /预处理 string s1 = textBox1.Text; string str1 = null; /去除换行和/注释 string str = textBox1.Lines; for (int i = 0; i str.Length; i+) if (stri.Contains(/) string strr = stri.Split(/); stri = strr0; for (int i = 0; i str.Length; i+) str1 += stri + ; /去除跳格，回车 if (str1.Contains(/v) str1 = str1.Replace(/v, ); if (str1.Contains(/r) str1 = str1.Replace(/r, ); if (str1.Contains(/n) str1 = str1.Replace(/n, ); if (str1.Contains(/t) str1 = str1.Replace(/t, ); /去除注释 while (str1.Contains(/*) & str1.Contains(*/) str1 = str1.Remove(str1.IndexOf(/*), str1.IndexOf(*/) - str1.IndexOf(/*) + 2); /去除多余空格 while (str1.Contains( ) str1 = str1.Replace( , ); return str1; private bool IsOperator(string str) for (int i = 0; i 运算符.Length; i+) if (str = 运算符i) return true; return false; private bool IsCommunity_character(string str) for (int i = 0; i 界符.Length; i+) if (str = 界符i) return true; return false; void analyze(string string1, ref string string2) string str = string1.Split(new char ); for (int i = 0; i str.Length - 1; i+) switch (liexingpanduan(stri) case 0: string2 += ( + stri + , + 保留字, + Search_Location(stri, 保留字) + ) + r + n; break; case 1: string2 += ( + stri + , + 标识符, + InsertId(stri, ref 标识符) + ) + r + n; break; case 2: string2 += ( + stri + , + 常数, + InsertId(stri, ref 常数) + ) + r + n; break; case 3: string2 += ( + stri + , + 运算符, + Search_Location(stri, 运算符) + ) + r + n; break; case 4: string2 += ( + stri + , + 界符, + Search_Location(stri, 界符) + ) + r + n; break; case 5: string2 += ( + stri + , + 未知符号, + InsertId(stri, ref 未知符号) + ) + r + n; break; private int liexingpanduan(string str) if(str = null) return -1; char a = str0; if (char.IsLetter(a) /首个字符为字母，则可能为保留字/标识符，也可能是未知字符 int i = 0; for (int k = 0; k 保留字.Length; k+) if (str = 保留字k) return 0;/保留字 for (i = 0; i = str.Length) return 1;/标识符 else if (char.IsDigit(a)/首个字符为数字，则可能为数字也可能为未知字符 int j = 0; for (j = 0; j = str.Length) return 2; /常数 else/首个字符不是字母/数字，则可能是运算符/界符或未知字符 if (IsOperator(str) return 3;/运算符 if (IsCommunity_character(str) return 4;/界符 return 5; private void button1_Click(object sender, EventArgs e) string textbox1text = textBox1.Text; if (textbox1text = ) MessageBox.Show(您没有输入任何字符！); return; textbox1text = Pretreatment(); string textbox2text = null; analyze(textbox1text, ref textbox2text); textBox2.Text = textbox2text; private void button2_Click(object sender, EventArgs e) DialogResult result = openFileDialog1.ShowDialog(); if (result = DialogResult.OK) string dir = openFileDialog1.FileName; string text = null; StreamReader sr; try sr = new StreamReader(dir, System.Text.Encoding.Default); catch MessageBox.Show(操作失败); return; while (sr.Peek() != -1) text += sr.ReadLine() ; sr.Close(); textBox1.Text = text; textBox1.Text = Pretreatment(); else MessageBox.Show(操作失败); private void button3_Click(object sender, EventArgs e) DialogResult result = saveFileDialog1.ShowDialog(); if (result = DialogResult.OK) string dir = saveFileDialog1.FileName; StreamWriter sw; try sw = File.CreateText(dir); catch MessageBox.Show(文件创建失败); return; string text = textBox2