參考：https://segmentfault.com/q/1010000012636380/a-1020000012640905

題目：統計文件中//和/* */註釋的個數，雙引號中的不算

import java.util.ArrayList;
import java.util.Scanner;

public class NoteCounter {

    public static void main(String[] args) throws Exception {
        // TODO 自動生成的方法存根
        Scanner in=new Scanner(System.in);
        ArrayList
 
<String> ve=new ArrayList<String>();
        while(in.hasNext()){
            String temp=in.nextLine();
            ve.add(temp);
            if(temp.equals("}"))break;
        }
        System.out.println(ve);
        System.out.println(operateNote(ve)[0]+"  "+operateNote(ve)[1]);
    }
    
 
public static int[] operateNote(ArrayList<String> list) throws Exception{
        
       String s = null;
       int countNote=0;
       int charInNote=0;
       for(int j=0;j<list.size();j++) {
           s=list.get(j);
           int note1=s.indexOf("/*");
           int note2=s.indexOf("//");
           
 
int note3=s.indexOf("*/");
           //int note4=s.indexOf("\"");

           String dm="\"(.*)\"";//雙引號
           String sm="\‘(.*)\‘";//單引號                 
           
          if(note1!=-1&&note3==-1) {//多行註釋
              countNote++;
              String ttt=list.get(j);
              list.set(j, ttt.substring(0, note1));
              charInNote+=s.substring(note1).length()+1;//+1是包括換行符
                            
                  s=list.get(++j);
              while((note3=s.indexOf("*/"))==-1) {
                    if((note2=s.indexOf("//"))!=-1) {
                        countNote++;
                    }
                    list.remove(j);
                    
                  charInNote+=s.length()+1;
                  if(j<list.size()-1) {
                      s=list.get(++j);
                  }else {
                      break;
                  }
              }
              list.remove(j);
              charInNote+=s.length();
              
          }else if(note2!=-1) {// "//"類的單行註釋
              countNote++;
              list.set(j, s.substring(0,note2));
              charInNote+=s.substring(note2).length()+1;
          }else if(note1!=-1&&note3!=-1) {//單行註釋
              countNote++;

              String m1=s.substring(0, note1);
              String m2=s.substring(note3+2);
              String m3=m1+m2;
              charInNote+=s.substring(note1, note3+2).length();
              list.set(j, m3);
          }else {//刪除輸出語句
              String rp=list.get(j);
              rp=rp.replaceAll(dm, "");
              list.set(j, rp);
          }
          
       }
       return new int[]{countNote,charInNote};

   }

}

測試數據：

// line comment //
/* block comment */ /* block comment2 */
int main(){
    char[] s="/* string */";
    return 0;
}

輸出結果：

3（註釋個數） 20（註釋中字符的個數）

package toutiao;
import java.util.ArrayList;import java.util.Scanner;
public class NoteCounter {
public static void main(String[] args) throws Exception {// TODO 自動生成的方法存根Scanner in=new Scanner(System.in); ArrayList<String> ve=new ArrayList<String>(); while(in.hasNext()){ String temp=in.nextLine(); ve.add(temp); if(temp.equals("}"))break; } System.out.println(ve); System.out.println(operateNote(ve)[0]+" "+operateNote(ve)[1]);}public static int[] operateNote(ArrayList<String> list) throws Exception{ String s = null; int countNote=0; int charInNote=0; for(int j=0;j<list.size();j++) { s=list.get(j); int note1=s.indexOf("/*"); int note2=s.indexOf("//"); int note3=s.indexOf("*/"); //int note4=s.indexOf("\"");
String dm="\"(.*)\"";//雙引號 String sm="\‘(.*)\‘";//單引號 if(note1!=-1&&note3==-1) {//多行註釋 countNote++; String ttt=list.get(j); list.set(j, ttt.substring(0, note1)); charInNote+=s.substring(note1).length()+1;//+1是包括換行符 s=list.get(++j); while((note3=s.indexOf("*/"))==-1) { if((note2=s.indexOf("//"))!=-1) { countNote++; } list.remove(j); charInNote+=s.length()+1; if(j<list.size()-1) { s=list.get(++j); }else { break; } } list.remove(j); charInNote+=s.length(); }else if(note2!=-1) {// "//"類的單行註釋 countNote++; list.set(j, s.substring(0,note2)); charInNote+=s.substring(note2).length()+1; }else if(note1!=-1&&note3!=-1) {//單行註釋 countNote++;
String m1=s.substring(0, note1); String m2=s.substring(note3+2); String m3=m1+m2; charInNote+=s.substring(note1, note3+2).length(); list.set(j, m3); }else {//刪除輸出語句 String rp=list.get(j); rp=rp.replaceAll(dm, ""); list.set(j, rp); } } return new int[]{countNote,charInNote};
}
}

java 統計文件註釋個數