copaci3.cpp: In function 'void bfs(int, int&)': copaci3.cpp:17: warning: comparison between signed and unsigned integer expressions copaci3.cpp: In function 'int main()': copaci3.cpp:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result copaci3.cpp:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result copaci3.cpp:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result copaci3.cpp:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result copaci3.cpp:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result