zigzag.cpp: In function 'bool operator<(const Poz&, const Poz&)': zigzag.cpp:16: warning: suggest parentheses around '&&' within '||' zigzag.cpp: In function 'int main()': zigzag.cpp:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result zigzag.cpp:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result zigzag.cpp:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result zigzag.cpp:50: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result