Compilare: user.cpp: In member function ‘bool ev::operator<(const ev&) const’: user.cpp:15: warning: suggest parentheses around ‘&&’ within ‘||’ user.cpp: In function ‘void add(int, int)’: user.cpp:36: warning: suggest parentheses around arithmetic in operand of ‘^’ user.cpp: In function ‘int query(int)’: user.cpp:42: warning: suggest parentheses around arithmetic in operand of ‘^’ user.cpp: In function ‘int main()’: user.cpp:50: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:73: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result