/in/foo.cc: In function 'int main()':
/in/foo.cc:24:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<va.size()){
        ~^~~~~~~~~~
/in/foo.cc:31:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<va.size(); i++){
               ~^~~~~~~~~~