Compilare: user.cpp: In function ‘void read()’: user.cpp:13: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:69: warning: suggest parentheses around comparison in operand of ‘^’ user.cpp: In function ‘int main()’: user.cpp:79: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:79: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:65: warning: ‘start’ may be used uninitialized in this function user.cpp:65: warning: ‘stop’ may be used uninitialized in this function