java怎么实现标识符查找功能_用java编写程序实现判断及识别标识符的功能

向右看齐 2022-11-04 00:47 142阅读 0赞

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这个是我做编译原理词法分析用的，可以识别包括，标示符，关键字，常数，32313133353236313431303231363533e78988e69d8331333262363035变量，操作符，界符等，你先拿去用吧！！

import java.io.FileReader;

//import java.io.FileWriter;

import java.io.IOException;

import java.io.FileOutputStream;

import java.io.OutputStreamWriter;

class Tools\{

public final int maxsize=200;

String savwd\[\]=\{"main","int","float","char","double","long","return","if","case","switch","break","default","printf","scanf","define","include"\};//保留字数组;

char operate\[\]=\{'=','>','

char seprate\[\]=\{',',';','\{','\}','"'\};//分隔符数组

String doperate\[\]=\{"==","+=","-=",">=","<=","!=","=","+","-","","!","\*","/","%","(",")","++","--","()"\};

class Monitor\{

public int flag;

public String string;

public class test \{

static Monitor analyste(char array\[\])\{//对读取的窜进行分析

Tools get=new Tools();

Monitor monitor=new Monitor();

int flag=0,numbercount=0;

int countnumber;

for(countnumber=0;array\[countnumber\]!='\\0';countnumber++);

String str=new String(array);

str=str.substring(0,countnumber);

for(int count=0;count

if(str.equals(get.savwd\[count\]))

flag=1;

break;

if(flag==1)\{//是否为关键字

monitor.flag=1 ;

else if(array\[0\]>='0'&&array\[0\]<='9')\{//判断是否为常量

numbercount=1;

for(int count=numbercount;count

if(array\[count\]>='0'&&array\[count\]<='9')

numbercount++;

if(numbercount

monitor.flag=2;

else if(numbercount==str.length())\{//判断是否是常量

monitor.flag=3;

else if((array\[0\]>='a'&&array\[0\]<='z')||(array\[0\]>='A'&&array\[0\]<='Z'))\{//判断是否是表示符

monitor.flag=4;

monitor.string=str;

return monitor;

static boolean iseprate(char o)//判断是否是分割符

Tools get=new Tools();

int flag=0;

for(int count=0;count

if(o==get.seprate\[count\])\{

flag=1;

break;

return (flag==1);

static boolean isoperate(char c)\{//判断是否是运算符

Tools get=new Tools();

int flag=0;

for(int count=0;count

if(c==(get.operate\[count\]))\{

flag=1;

break;

return (flag==1);

static Monitor analystoperate(char doubles\[\])//此函数用于分析操作数组，并返回分析状态值给MONITOR，共输出程序调用

int count;

int flag=0;

Tools tl=new Tools();

Monitor temp=new Monitor();

String str=new String(doubles);

for( count=0;doubles\[count\]!='\\0';count++);

str=str.substring(0,count);

for(int i=0;i

if(str.equals(tl.doperate\[i\]))\{

flag=1;

break;

temp.flag=flag;

temp.string=str;

return temp;

public static void main(String args\[\])throws IOException\{

Tools get=new Tools();

FileReader in=new FileReader("C:\\\\myjava\\\\testdata.txt");

FileOutputStream file=new FileOutputStream("C:\\\\myjava\\\\result.txt",true);

OutputStreamWriter out=new OutputStreamWriter(file);

int temp;

int flag=0;

char operate\[\]=new char\[get.maxsize\];

int operatecount=0;

int operateflag=0;

Monitor result=new Monitor();

Monitor oresult=new Monitor();

char temparray\[\]=new char\[get.maxsize\];

System.out.println("符号 名称 说明");

out.write("符号 名称 说明"+"\\n");

System.out.println();

while((temp=in.read())!=-1)\{//读文件

if(temp!=' '&&!iseprate((char)temp)&&!isoperate((char)temp)&&temp!='\\n')

temparray\[flag++\]=(char)temp;

else \{

result=analyste(temparray);

char character\[\]=\{(char)temp\};

String word=result.string;

if(result.flag==1)\{

System.out.println(word+" 关键字");

out.write(word+" 关键字");

out.write("\\n");

if(result.flag==2)\{

System.out.println(word+" 标示符 error");

out.write(word+" 标示符 error");

out.write("\\n");

if(result.flag==3)\{

System.out.println(word+" 常量 ");

out.write(word+" 常量 ");

out.write("\\n");

if(result.flag==4)\{

System.out.println(word+" 标示符");

out.write(word+" 标示符");

out.write("\\n");

if(result.flag==5)\{

System.out.println(word+" 关键字");

out.write(word+" 关键字");

out.write("\\n");

if(iseprate((char)temp))

String s=new String(character);

System.out.println(s+" 分隔符");

out.write(s+" 分隔符");

out.write("\\n");

if(isoperate((char)temp))\{//判断是否是操作符并保存操作符到相应的数组

operate\[operatecount++\]=(char)temp;

operateflag++;

//continue;

else if(operateflag!=0)\{

oresult=analystoperate(operate);//分析操作符数组

if(oresult.flag==1)\{//输出正确的操纵符

out.write(oresult.string+" 操作符"+"\\n");

System.out.println(oresult.string+" 操作符");

else\{//输出错误操作符

out.write(oresult.string+" 操作符"+" ERROR"+"\\n");

System.out.println(oresult.string+" 操作符"+" ERROR");

for(int count=0;count

operate\[count\]='\\0';

operateflag=0;

operatecount=0;

flag=0;

for(int count=0;count

temparray\[count\]='\\0';

continue;

System.out.println("分析完毕");

in.close();

out.close();

/\*程序说明：

\* 此程序用于简单C语言程序的词法分析，如果想扩大其检索的范围包括语言的种类等等，可在Tools类内部进行扩充文件。

\* 此程序有一个弊端，操作符的输出有一定的滞后性，还有待改进

\*/

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java怎么实现标识符查找功能_用java编写程序实现判断及识别标识符的功能

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