Compilare: user.cpp: In function ‘int main()’: user.cpp:14:15: warning: variable ‘j’ set but not used [-Wunused-but-set-variable] int i, n, j, k; ^ user.cpp:14:18: warning: unused variable ‘k’ [-Wunused-variable] int i, n, j, k; ^ user.cpp:31:29: warning: ‘s’ may be used uninitialized in this function [-Wmaybe-uninitialized] fprintf(fout, "%lld", s); ^