/in/foo.cc: In function 'int main()':
/in/foo.cc:8:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<=strlen(s);i+=2) sum1+=(int)s[i];
                 ^
/in/foo.cc:9:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=1;i<=strlen(s);i+=2) sum2+=(int)s[i];
                 ^