编译原理实验之词法分析程序(增加从控制台输入程序内容)

package java_project; import java.io.FileInputStream; import java.io.InputStreamReader; import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class MyMain{ Set<String> keyWordsSet = new HashSet<String>(); Set<String> operatorSet = new HashSet<String>(); Set<String> separatorSet= new HashSet<String>(); String fileStr = "",currentStr=""; int index = -1; public static void main(String[] args){ MyMain my = new MyMain(); MyUtil.readProgram(); my.initSets(); my.readFile(); my.start(); } private void start(){ for(int i=0;i<fileStr.length();i++){ currentStr = ""; String s = fileStr.charAt(i)+""; index = i; if(Character.isLetter(fileStr.charAt(i))||s.equals("_")){ dealLetter(); }else if(Character.isDigit(fileStr.charAt(i))){ dealDigit(); }else if(separatorSet.contains(s)){ dealSeparator(); }else if(operatorSet.contains(s)||s.equals("!")){ dealOperator(); } i = index; } } /** * 初始化集合 */ private void initSets(){ String keyWords[] = {"if","int","for","while","do","return","break","continue"}; keyWordsSet.addAll(Arrays.asList(keyWords)); String operators[] = {"+","-","*","/","=",">","<",">=","<=","!="}; operatorSet.addAll(Arrays.asList(operators)); String separators[] = {",",";","{","}",")","("}; separatorSet.addAll(Arrays.asList(separators)); } /** * 初始化需要读取的程序文件 */ private void readFile(){ try { InputStreamReader reader = new InputStreamReader(new FileInputStream("jc.c")); int temp; while((temp=reader.read())!=-1) fileStr+=((char)temp); } catch (Exception e){} } private void dealLetter(){ currentStr+=fileStr.charAt(index); for(int i=index+1;i<fileStr.length();i++){ String s = fileStr.charAt(i)+""; index = i; if(s.equals("_")||Character.isLetterOrDigit(fileStr.charAt(i))){ currentStr+=fileStr.charAt(i); }else{ break; } } index--; if(keyWordsSet.contains(currentStr)){ System.out.println("(1,"+"\""+currentStr+"\")"); }else{ System.out.println("(2,"+"\""+currentStr+"\")"); } } private void dealDigit(){ currentStr+=fileStr.charAt(index); for(int i=index+1;i<fileStr.length();i++){ index = i; if(Character.isDigit(fileStr.charAt(i))){ currentStr+=fileStr.charAt(i); }else{ break; } } index--; System.out.println("(3,"+"\""+currentStr+"\")"); } private void dealSeparator() { currentStr+=fileStr.charAt(index); System.out.println("(5,"+"\""+currentStr+"\")"); } private void dealOperator(){ currentStr = fileStr.charAt(index)+""; if(index+1<fileStr.length()){ String s1 = fileStr.charAt(index)+""; s1 += fileStr.charAt(index+1)+""; if(operatorSet.contains(s1)){ System.out.println("(4,"+"\""+s1+"\")"); index++; }else{ System.out.println("(4,"+"\""+currentStr+"\")"); } }else{ System.out.println("(4,"+"\""+currentStr+"\")"); } } }