Compilare: user.cpp: In function ‘int write(int, int)’: user.cpp:22:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:49:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i(0);i<vec.size();i++) out<< vec[i]<<' '; ^