Compilare: user.cpp: In function ‘void query(node*)’: user.cpp:97:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j, x, y; ^ user.cpp:97:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, x, y; ^ user.cpp: In function ‘int main()’: user.cpp:135:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("votare.in","r",stdin); ^ user.cpp:136:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("votare.out","w",stdout); ^ user.cpp:138:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^ user.cpp: In member function ‘void op::read()’: user.cpp:36:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &type, &x, &y); ^