/in/foo.cc: In function 'double confuse(double)':
/in/foo.cc:40:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<strlen(ch);i++)
             ~^~~~~~~~~~~
/in/foo.cc:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(j=0;j<strlen(ch)-i-1;j++)
                 ~^~~~~~~~~~~~~~~
/in/foo.cc:50:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<strlen(ch);i++)
             ~^~~~~~~~~~~