去掉comments

三种comments:

 /* Test program */ 

    int main()  

    {           

       // variable declaration 

       int a, b, c;    

       /* This is a test  

           multiline     

           comment for   

           testing */      

       a = b + c;       

    } 

 import java.util.*;
 public class removeComments{
     public static void main(String [] args){
         String file = "   /* Test program */ \n" +
                   "   int main()  \n" +
                   "   {           \n" +
                   "      // variable declaration \n" +
                   "      int a, b, c;    \n" +
                   "      /* This is a test  \n" +
                   "          multiline     \n" +
                   "          comment for   \n" +
                   "          testing */      \n" +
                   "      a = b + c;       \n" +
                   "   }           \n";
         System.out.println(file);
         System.out.println(removeComments(file));
     }

     private static String removeComments(String s){
         if(s == null || s.length() == 0){
             return s;
         }
         StringBuilder res = new StringBuilder();
         boolean sCom = false;
         boolean mCom = false;

         for(int i = 0; i<s.length(); i++){
             // System.out.println("i is " + i + "sCom, mCom  = " + sCom + mCom);
             if(sCom && (s.charAt(i) == '\n')){
                 System.out.println("i is " + i);
                 sCom = false;
             }else if(mCom && s.charAt(i) == '*' && i+1<s.length() && s.charAt(i+1) == '/'){
                 mCom = false;
                 i++;
             }else if(sCom || mCom){
                 continue;
             }else if(s.charAt(i) == '/' && i+1 < s.length() && s.charAt(i+1) == '/'){
                 sCom = true;
                 i++;
             }else if(s.charAt(i) == '/' && i+1 <s.length() && s.charAt(i+1) == '*'){
                 mCom = true;
                 i++;
             }else{
                 res.append(s.charAt(i));
             }
         }
         return res.toString();
     }

 }