java词法分析简单代码 编译程序词法分析

请用JAVA编程输入一个语句进行词法分析

我最近正在学编译原理，我有c语言实现的词法分析程序，不知可不可以，识别的是TEST语言的单词。

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#includestdio.h

#includectype.h

#includestring.h

#define keywordSum 8

char * keyword[keywordSum] = {"do", "else", "for", "if", "int", "read", "while", "write"};

char singleword[50] = "+-*(){};,:";

char doubleword[10] = "=!|";

char Scanin[300], Scanout[300];

FILE * fin, * fout;

int binaryFind(int low, int high, char * c1, char ** c2) {

int mid;

if(low high) return -1;

mid = (low+high)/2;

if(strcmp(c1, c2[mid]) == 0) return mid;

else if(strcmp(c1, c2[mid]) 0) return binaryFind(mid+1, high, c1, c2);

else return binaryFind(low, mid-1, c1, c2);

}

int TESTscan() {

char ch, token[40];

int es = 0, j, n;

printf("请输入源文件名(包括路径):");

scanf("%s", Scanin);

printf("请输入词法分析输出文件名(包括路径):");

scanf("%s", Scanout);

if((fin=fopen(Scanin, "r")) == NULL) {

printf("\n打开词法分析输入文件出错!\n");

return 1;

}

if((fout=fopen(Scanout, "w")) == NULL) {

printf("\n创建词法分析输出文件出错!\n");

return 2;

}

// printf("%c", getc(fin));

ch = getc(fin);

while(ch != EOF) {

while(ch==' ' || ch=='\n' || ch=='\t') {

ch = getc(fin);

}

if(isalpha(ch)) { //标识符

token[0] = ch;

j = 1;

ch = getc(fin);

while(isalnum(ch)) { //判断当前字符是否是字母或数字

token[j++] = ch;

ch = getc(fin);

}

token[j] = '\0';

// printf("%s", token);

n = binaryFind(0, keywordSum-1, token, keyword);

if(n 0 ) {

fprintf(fout, "%s\t%s\n", "ID", token);

} else {

fprintf(fout, "%s\t%s\n", token, token);

}

} else if(isdigit(ch)) { //数字

token[0] = ch;

j = 1;

ch = getc(fin);

while(isdigit(ch)) {

token[j++] = ch;

ch = getc(fin);

}

token[j] = '\0';

fprintf(fout, "%s\t%s\n", "NUM", token);

} else if(strchr(singleword, ch) 0) { //singleword

token[0] = ch;

token[1] = '\0';

ch = getc(fin);

fprintf(fout, "%s\t%s\n", token, token);

} else if(strchr(doubleword, ch) 0) { //doubleword

token[0] = ch;

ch = getc(fin);

if(ch=='=' (token[0]==''||token[0]=='' || token[0] == '!')) {

token[1] = ch;

token[2] = '\0';

ch = getc(fin);

} else if((ch=='')||(ch=='|')||(ch=='=') ch==token[0]) {

token[1] = ch;

token[2] = '\0';

ch = getc(fin);

} else {

token[1] = '\0';

}

fprintf(fout, "%s\t%s\n", token, token);

} else if(ch == '/') { //注释

ch = getc(fin);

if(ch == '*') {

char ch1;

ch1 = getc(fin);

do {

ch = ch1;

ch1 = getc(fin);

} while((ch!='*'||ch1!='/') ch1!=EOF);

ch = getc(fin);

} else {

token[0] = '/';

token[1] = '\0';

fprintf(fout, "%s\t%s\n", token, token);

}

} else {

token[0] = ch;

token[1] = '\0';

ch = getc(fin);

es = 3;

fprintf(fout, "%s\t%s\n", "ERROR", token);

}

}

fclose(fin);

fclose(fout);

return es;

}

void main() {

int es = 0;

es = TESTscan();

if(es 0) {

printf("词法分析有错, 编译停止!\n");

} else {

printf("词法分析成功!\n");

}

}

帮忙写份词法分析程序，C,C++,java,C#都行，越简单越好！

这个我做了一个类似的，识别字符串的，发给你，你在这个基础上改一下吧，哥最近在忙软考不然帮你做做。

程序识别的字符串输入的格式：

1、输入如下正确的常量说明串：

const count=10,sum=81.5,char1=‘f’,max=169,str1=“h*54 2..4S!AAsj”, char2=‘@’,str2=“aa!+h”；

输出：

count(integer,10)

sum(float,81.5)

char1(char, ‘f’)

max(integer,169)

str1(string,“h*54 2..4S!AAsj”)

char2(char, ‘@’)

str2(string,“aa!+h”)

int_num=2; char_num=2; string_num=2; float_num=1.

程序如下：

#includeiostream

using namespace std;

int char_num=0,string_num=0,int_num=0,float_num=0; // 字符值类型，0=字符，1=字符串，2=整数，3=浮点数

class zifu //建立字符类，存储一个字符串的信息

{

public:

int i;

char name[20];

char data[20];

int dataname;

void display(){

i=0;

while(name[i]!='\0')

{

coutname[i];

i++;

}

cout"=";

i=0;

while(data[i]!='\0'){

coutdata[i];

}

coutendl;

coutdatanameendl;

}

};

void input(char a[]) //输入函数

{

char stand[6]="const";

int i=0,judge=0;

gets(a);

for(i=0;i5;i++)

{

if(a[i]==stand[i])

judge++;

}

if(judge!=5 || a[5]!=' ')

{

cout"It is not a constant declaration statement! ";

cout"Please input a string again!"endl;

input(a);

}

}

void sort(zifu aclass[],char b[],int integer,int tag) //识别函数,tag 类标记 ,integer 当前查找的位置

{

int i=0;

while(b[++integer]!='=')

{

if(b[integer]!=' ')

aclass[tag].name[i]=b[integer];

i++; //获取字符串名

}

aclass[tag].name[i]='\0';

i=0;

++integer;

while(b[integer]!=',' b[integer]!=';') //获取字符串值、值类型

{

if(b[integer]='0' b[integer]='9')// 字符值类型，0=字符，1=字符串，2=整数，3=浮点数

aclass[tag].dataname=2;

else if(b[integer]=='.') //浮点数判断。。。真麻烦

{ aclass[tag].dataname=3;

while(b[integer]!=',' b[integer]!=';'){

aclass[tag].data[i]=b[integer];

integer++;i++;}}

else if(b[integer]='a' b[integer]='z')

aclass[tag].dataname=0;

else if(b[integer]='A' b[integer]='Z')

aclass[tag].dataname=1;

else if(b[integer]=='\'' || b[integer]=='\'')

aclass[tag].dataname=0;

else if(b[integer]=='"' || b[integer]=='"')

aclass[tag].dataname=1;

if(b[integer]!=',' b[integer]!=';')

{

aclass[tag].data[i]=b[integer];

i++;

++integer;

}

}

aclass[tag].data[i]='\0';

++tag;

if(b[integer]!=';')

sort(aclass,b,integer,tag);

}

void display(zifu a) //输出函数

{

int n=0;

int q=0;

while (a.name[n]!='\0')

{couta.name[n];

n++;}

cout"(";

switch (a.dataname)

{case 0:

cout"char";

char_num++;

break;

case 1:

cout"string";

string_num++;

break;

case 2:

cout"integer";

int_num++;

break;

case 3:

cout"float";

float_num++;

break;

default:

cout"type error";}

cout',';

while (a.data[q]!='\0')

{couta.data[q];

q++;}

cout")"endl;

}

void main()

{

zifu teger[10];

char c[100];

int tag0=0,integer0=5;

int m=0;

while(1){

cout"please input:"endl;

input(c);

// cout"0=字符，1=字符串，2=整数，3=浮点数"endl;

sort(teger,c,integer0,tag0);

// cout"字符串数量="tag0endl;

for(m=0;mtag0;m++)

{display(teger[m]);}

coutendl"int_num="int_num"; ""char_num="char_num"; ";

cout"string_num="string_num"; ""float_num="float_numendlendl;

}

}

怎么用java写一个词法分析器

首先看下我们要分析的代码段如下：

输出结果如下：

输出结果(a).PNG

输出结果(b).PNG

输出结果(c).PNG

括号里是一个二元式：（单词类别编码，单词位置编号）

代码如下：

?

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package Yue.LexicalAnalyzer; import java.io.*; /* * 主程序 */public class Main {  public static void main(String[] args) throws IOException {    Lexer lexer = new Lexer();    lexer.printToken();    lexer.printSymbolsTable();  }}

?

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package Yue.LexicalAnalyzer; import java.io.*;import java.util.*; /* * 词法分析并输出 */public class Lexer {  /*记录行号*/  public static int line = 1;  /*存放最新读入的字符*/  char character = ' ';   /*保留字*/  HashtableString, KeyWord keywords = new HashtableString, KeyWord();  /*token序列*/  private ArrayListToken tokens = new ArrayListToken();  /*符号表*/  private ArrayListSymbol symtable = new ArrayListSymbol();   /*读取文件变量*/  BufferedReader reader = null;  /*保存当前是否读取到了文件的结尾*/  private Boolean isEnd = false;   /* 是否读取到文件的结尾 */  public Boolean getReaderState() {    return this.isEnd;  }   /*打印tokens序列*/  public void printToken() throws IOException {    FileWriter writer = new FileWriter("E:\\lex.txt");    System.out.println("词法分析结果如下：");    System.out.print("杜悦-2015220201031\r\n\n");    writer.write("杜悦-2015220201031\r\n\r\n");    while (getReaderState() == false) {      Token tok = scan();      String str = "line " + tok.line + "\t(" + tok.tag + "," + tok.pos + ")\t\t"          + tok.name + ": " + tok.toString() + "\r\n";      writer.write(str);      System.out.print(str);    }    writer.flush();   }   /*打印符号表*/  public void printSymbolsTable() throws IOException {    FileWriter writer = new FileWriter("E:\\symtab1.txt");    System.out.print("\r\n\r\n符号表\r\n");    System.out.print("编号\t行号\t名称\r\n");    writer.write("符号表\r\n");    writer.write("编号 " + "\t行号 " + "\t名称 \r\n");    IteratorSymbol e = symtable.iterator();    while (e.hasNext()) {      Symbol symbol = e.next();      String desc = symbol.pos + "\t" + symbol.line + "\t" + symbol.toString();      System.out.print(desc + "\r\n");      writer.write(desc + "\r\n");    }     writer.flush();  }   /*打印错误*/  public void printError(Token tok) throws IOException{    FileWriter writer = new FileWriter("E:\\error.txt");    System.out.print("\r\n\r\n错误词法如下：\r\n");    writer.write("错误词法如下：\r\n");    String str = "line " + tok.line + "\t(" + tok.tag + "," + tok.pos + ")\t\t"        + tok.name + ": " + tok.toString() + "\r\n";    writer.write(str);  }   /*添加保留字*/  void reserve(KeyWord w) {    keywords.put(w.lexme, w);  }   public Lexer() {    /*初始化读取文件变量*/    try {      reader = new BufferedReader(new FileReader("E:\\输入.txt"));    } catch (IOException e) {      System.out.print(e);    }     /*添加保留字*/    this.reserve(KeyWord.begin);    this.reserve(KeyWord.end);    this.reserve(KeyWord.integer);    this.reserve(KeyWord.function);    this.reserve(KeyWord.read);    this.reserve(KeyWord.write);    this.reserve(KeyWord.aIf);    this.reserve(KeyWord.aThen);    this.reserve(KeyWord.aElse);  }   /*按字符读*/  public void readch() throws IOException {    character = (char) reader.read();    if ((int) character == 0xffff) {      this.isEnd = true;    }  }   /*判断是否匹配*/  public Boolean readch(char ch) throws IOException {    readch();    if (this.character != ch) {      return false;    }     this.character = ' ';    return true;  }   /*数字的识别*/  public Boolean isDigit() throws IOException {    if (Character.isDigit(character)) {      int value = 0;      while (Character.isDigit(character)) {        value = 10 * value + Character.digit(character, 10);        readch();      }       Num n = new Num(value);      n.line = line;      tokens.add(n);      return true;    } else      return false;  }   /*保留字、标识符的识别*/  public Boolean isLetter() throws IOException {    if (Character.isLetter(character)) {      StringBuffer sb = new StringBuffer();       /*首先得到整个的一个分割*/      while (Character.isLetterOrDigit(character)) {        sb.append(character);        readch();      }       /*判断是保留字还是标识符*/      String s = sb.toString();      KeyWord w = keywords.get(s);       /*如果是保留字的话，w不应该是空的*/      if (w != null) {        w.line = line;        tokens.add(w);      } else {        /*否则就是标识符，此处多出记录标识符编号的语句*/        Symbol sy = new Symbol(s);        Symbol mark = sy;      //用于标记已存在标识符        Boolean isRepeat = false;        sy.line = line;        for (Symbol i : symtable) {          if (sy.toString().equals(i.toString())) {            mark = i;            isRepeat = true;          }        }        if (!isRepeat) {          sy.pos = symtable.size() + 1;          symtable.add(sy);        } else if (isRepeat) {          sy.pos = mark.pos;        }        tokens.add(sy);      }      return true;    } else      return false;  }   /*符号的识别*/  public Boolean isSign() throws IOException {    switch (character) {      case '#':        readch();        AllEnd.allEnd.line = line;        tokens.add(AllEnd.allEnd);        return true;      case '\r':        if (readch('\n')) {          readch();          LineEnd.lineEnd.line = line;          tokens.add(LineEnd.lineEnd);          line++;          return true;        }      case '(':        readch();        Delimiter.lpar.line = line;        tokens.add(Delimiter.lpar);        return true;      case ')':        readch();        Delimiter.rpar.line = line;        tokens.add(Delimiter.rpar);        return true;      case ';':        readch();        Delimiter.sem.line = line;        tokens.add(Delimiter.sem);        return true;      case '+':        readch();        CalcWord.add.line = line;        tokens.add(CalcWord.add);        return true;      case '-':        readch();        CalcWord.sub.line = line;        tokens.add(CalcWord.sub);        return true;      case '*':        readch();        CalcWord.mul.line = line;        tokens.add(CalcWord.mul);        return true;      case '/':        readch();        CalcWord.div.line = line;        tokens.add(CalcWord.div);        return true;      case ':':        if (readch('=')) {          readch();          CalcWord.assign.line = line;          tokens.add(CalcWord.assign);          return true;        }        break;      case '':        if (readch('=')) {          readch();          CalcWord.ge.line = line;          tokens.add(CalcWord.ge);          return true;        }        break;      case '':        if (readch('=')) {          readch();          CalcWord.le.line = line;          tokens.add(CalcWord.le);          return true;        }        break;      case '!':        if (readch('=')) {          readch();          CalcWord.ne.line = line;          tokens.add(CalcWord.ne);          return true;        }        break;    }    return false;  }    /*下面开始分割关键字，标识符等信息*/  public Token scan() throws IOException {    Token tok;    while (character == ' ')      readch();    if (isDigit() || isSign() || isLetter()) {      tok = tokens.get(tokens.size() - 1);    } else {      tok = new Token(character);      printError(tok);    }    return tok;  }}