编译原理-词法分析实验报告-java版.doc

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1、词法分析代码。importjava.io.*;importjava.util.Vector;importjava.util.regex.*;publicclassCompiler{publicstaticStringstringCompiler="";privatestaticfinalString[]KEY_WORD={"if","then","while","do","read","write","call","begin","end","const","var","procedure","odd"};privatestaticbooleani

2、sKeyWord(Strings)//是否是关键字{booleanb=false;for(inti=0;isheet

3、=newVector(8);Fileresult=newFile("result.txt");Fileresult1=newFile("result1.txt");booleanwork(){System.out.println("输入PL/O语言为：");try{FileWriterfw1=newFileWriter(result1);BufferedWriterbw1=newBufferedWriter(fw1);FileReaderfr1=newFileReader("input.txt");BufferedReaderbr

4、1=newBufferedReader(fr1);Strings=br1.readLine();label1:while(s!=null){for(inti=0;i

5、);s=br1.readLine();continuelabel1;}elseif(s.indexOf("/*")!=-1)//'/'符和'*'符{s=s.substring(0,s.indexOf("/*"));s.replaceAll("t","");s.replaceAll("","");s.toLowerCase();bw1.write(s.substring(0,i));System.out.println(s);s=s.substring(i,s.length());while(s!=null){if(s.indexOf("*/"

6、)!=-1){s=s.substring(s.lastIndexOf("*/"),s.length());s=s.replaceAll("t","");s=s.replaceAll("","");s=s.toLowerCase();bw1.write(s);System.out.println(s);bw1.newLine();s=br1.readLine();continuelabel1;}else{s=br1.readLine();}}}else{s=s.replaceAll("t","");s=s.replaceAll("",""

7、);s=s.toLowerCase();bw1.write(s);System.out.println(s);bw1.newLine();s=br1.readLine();continuelabel1;}}}br1.close();bw1.close();returntrue;}catch(IOExceptione){e.printStackTrace();returnfalse;}finally{}}voidanalyser(){try{BufferedReaderbr=newBufferedReader(newFileReader(result

8、1));BufferedWriterbw=newBufferedWriter(newFileWriter(result))