Full Text Search index not showing exact search result

Hi,

 i have created the full text index on the table candidates.

I am Storing candidates resume in c_resume text filed.

select * from candidates WHERE contains(c_resume_text,'C++') -It shwoing c++ and also other than c++ results.

select * from candidates WHERE contains(c_resume_text,'C++11') -It showing results.

select * from candidates WHERE contains(c_resume_text,'C++1') -It showing Zero results.

Can you please help me why the above first query will showing all the records of c++ and also other than c++.

second query it not showing any results but third query showing result?

why it ignoring the third query compare to second query?

Please help me