/in/foo.cc: In function 'int main()':
/in/foo.cc:23:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i = 1 ; i < t1.size() ; i++)
                 ~~^~~~~~~~~~~
/in/foo.cc:28:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(i==t1.size())
        ~^~~~~~~~~~~
/in/foo.cc:32:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i = 1 ; i < t1.size() ; i++)
                 ~~^~~~~~~~~~~
/in/foo.cc:37:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(i==t1.size())
        ~^~~~~~~~~~~