Compilare: user.cpp: In function ‘int main()’: user.cpp:55:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gbc.in","r",stdin); ^ user.cpp:56:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gbc.out","w",stdout); ^ user.cpp:58:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &a, &b); ^ user.cpp:60:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s + 1); ^