Compilare: user.cpp: In function ‘int main()’: user.cpp:35:9: warning: unused variable ‘a’ [-Wunused-variable] int n, a, b, m; ^ user.cpp:35:12: warning: unused variable ‘b’ [-Wunused-variable] int n, a, b, m; ^ user.cpp:29:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vmin.in", "r", stdin); ^ user.cpp:30:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vmin.out", "w", stdout); ^