/in/foo.cc: In function 'int main()':
/in/foo.cc:10:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i=0;i<strlen(s);i++)
              ~^~~~~~~~~~
/in/foo.cc:42:40: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (ans<=0.000&&ans>-0.0005) printf("%c=0.000",c);
                                  ~~~~~~^~~~~~~~~~~~~~