Compilare: user.cpp: In function ‘void update(int)’: user.cpp:12: warning: suggest parentheses around arithmetic in operand of ‘^’ user.cpp: In function ‘int query(int)’: user.cpp:21: warning: suggest parentheses around arithmetic in operand of ‘^’ user.cpp: In function ‘int main()’: user.cpp:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result