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 */ 
" + 
                  "   int main()  
" +
                  "   {           
" +
                  "      // variable declaration 
" +
                  "      int a, b, c;    
" +
                  "      /* This is a test  
" +
                  "          multiline     
" +
                  "          comment for   
" +
                  "          testing */      
" +
                  "      a = b + c;       
" +
                  "   }           
";
        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) == '
')){
                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();
    }


}