编译原理词/语法分析

效果：







代码：

using System;


[code]using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace 词法分析

{

public partial class Form1 : Form

{

public int Count = 0;

public bool EndFlag = false;

public char MString;

public string StartString = "";

public string EndString = "";

public string FirstString = " ";

public string Sym = " ";

Dictionary<string, int> Table = new Dictionary<string, int>();

public Form1()

    {

InitializeComponent();

}

private void textBox1_TextChanged(object sender, EventArgs e)

    {

if (textBox1.Text == "")

{

Count = 0;

StartString = "";

FirstString = " ";

EndString = "";

this.pictureBox2.Image = null;

this.label2.Text = "";

MyDataView.Rows.Clear();

}

if (textBox1.Text.Length - 1>=0)

MString = textBox1.Text.Substring(textBox1.Text.Length - 1, 1)[0];

else MString =' ';

Table = new Dictionary<string, int>();

Table.Add("begin", 1);

Table.Add("end", 2);

Table.Add("if", 3);

Table.Add("then", 4);

Table.Add("else", 5);

Table.Add("while", 6);

Table.Add("do", 7);

Table.Add("标识符", 8);

Table.Add("整常数", 9);

Table.Add("+", 10);

Table.Add("-", 11);

Table.Add("*", 12);

Table.Add("/", 13);

Table.Add("<=", 14);

Table.Add("<>", 15);

Table.Add("<", 16);

Table.Add(":", 17);

Table.Add(":=", 18);

Table.Add(";", 19);

Table.Add("(", 18);

Table.Add(")", 19);

Table.Add("$", 20);

Table.Add("id", 21);

EndProc();

}

private void EndProc()

    {

if (char.IsLetter(FirstString[0]))

{    

    if (char.IsLetter(MString) || char.IsDigit(MString))

    {

        StartString += MString;

        FirstString = StartString[0].ToString();

}

    else

    {

        if (MString != ' ' || MString != '\n')

{

EndString = StartString;

StartString = MString.ToString();

FirstString = StartString[0].ToString();

}

        switch (EndString)

{

case "begin":

    EndString = "begin";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "end":

    EndString = "end";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "if":

    EndString = "if";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "then":

    EndString = "then";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "else":

    EndString = "else";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "while":

    EndString = "while";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "do":

    EndString = "do";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

case "id":

    EndString = "id";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

default :

    EndString = "标识符";

    MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

StartString = "";

FirstString = " ";

    break;

}

        EndProc();

        EndFlag = true;        

}    

}

else if (char.IsDigit(FirstString[0]))

{

    if (char.IsDigit(MString))

    {

        StartString += MString;

        FirstString = StartString[0].ToString();

}

    else

    {        

        if (MString != ' ' || MString != '\n')

{

EndString = StartString;

StartString = MString.ToString();

FirstString = StartString[0].ToString();

}

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "整常数";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        EndProc();

}

}

else if (FirstString == "<")

{

    if (MString=='=')

    {

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "<=";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

}

    else if (MString == '>')

    {

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "<>";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

}

    else

    {

        if (MString != ' ' || MString != '\n')

{

EndString = StartString;

StartString = MString.ToString();

FirstString = StartString[0].ToString();

}

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "<";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        EndProc();

}

}

else if (FirstString == ":")

{

    if (MString == '=')

    {

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = ":=";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

}

    else

    {

        if (MString != ' ' || MString != '\n')

{

EndString = StartString;

StartString = MString.ToString();

FirstString = StartString[0].ToString();

}

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = ":";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        EndProc();

}

}

else switch (MString)

{

    case '+':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "+";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case '-':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "-";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case '*':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "*";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case '/':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "/";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case '(':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "(";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case ')':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = ")";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case '$':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = "$";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case ';':

    StartString = "";

    FirstString = " ";

        EndFlag = true;

        EndString = ";";

        MyDataView.Rows.Add(++Count, EndString, Table[EndString]);

        break;

    case '<':

        StartString = MString.ToString();

        FirstString = StartString[0].ToString();

        break;

    case ':':

        StartString = MString.ToString();

        FirstString = StartString[0].ToString();

        break;

    default:

        if (char.IsLetter(MString))

{

StartString += MString;

FirstString = StartString[0].ToString();

}

        if (char.IsDigit(MString))

{

StartString += MString;

FirstString = StartString[0].ToString();

}

        break;

}

}

private void button1_Click(object sender, EventArgs e)

    {

Count = 0;

Scaner();

E();

if (Sym == "$")

{

    if(this.pictureBox2.Image == null)

    this.pictureBox2.Image = Image.FromFile("./图片/笑脸.jpg");

    this.label2.Text = "Excellent work！！";

}

else

    Error();

}

private void Scaner()

    {

try

{ 

    Sym = MyDataView[1, Count++].Value.ToString(); 

}

catch 

{

    MessageBox .Show ("请输入终止符$!!");

}

}

private void E()

    {

T();

Epie();

}

private void Epie()

    {

if (Sym == "+")

{

    Scaner();

    T();

    Epie();

}

else if (Sym != ")" && Sym != "$")

    Error();

}

private void T()

    {

F();

Tpie();

}

private void Tpie()

    {

if (Sym == "*")

{

    Scaner();

    F();

    Tpie();

}

else if (Sym != ")" && Sym != "$" && Sym != "+")

    Error();

}

private void F()

    {

if (Sym == "id")

    Scaner();

else if (Sym == "(")

{

    Scaner();

    E();

    if (Sym == ")")

        Scaner();

    else Error();

}

else Error();

}

private void Error()

    {

this.pictureBox2.Image = Image.FromFile("./图片/哭脸.jpg");

this.label2.Text = "Error input！！";

}

}

}

[/code]

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