xor.cpp: In function 'void read_input()': xor.cpp:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result xor.cpp:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result xor.cpp: In function 'long long int solve()': xor.cpp:102: warning: no return statement in function returning non-void xor.cpp: In function 'int main()': xor.cpp:106: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result xor.cpp:107: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result