/in/foo.cc: In function 'int main()':
/in/foo.cc:9:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<strlen(s);++i)
                 ^
/in/foo.cc:33:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<strlen(s);++i){
                ^