/in/foo.cc: In function 'int main()':
/in/foo.cc:7:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<strlen(a);i++){
                 ~^~~~~~~~~~
/in/foo.cc:8:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      for(int j=1;j<strlen(b);j++){
                  ~^~~~~~~~~~