/in/foo.cc: In function 'int main()':
/in/foo.cc:12:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a.size();i++)
              ~^~~~~~~~~
/in/foo.cc:15:28: error: 'memset' was not declared in this scope
  memset(big, 0, sizeof(big));
                            ^
/in/foo.cc:16:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<b.size();i++)
              ~^~~~~~~~~
/in/foo.cc:21:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < b.size(); i++) {
                  ~~^~~~~~~~~~