/in/foo.cc: In function 'int main(int, char**)':
/in/foo.cc:31:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<v.size();i++)
                  ^
/in/foo.cc:35:20: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
     system("pause");
                    ^