/in/foo.cc: In function 'int main()':
/in/foo.cc:47:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=0;j<str.length();j++)
                         ~^~~~~~~~~~~~~
/in/foo.cc:46:11: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
         if(c=='1')
           ^