graf.cpp: In function 'void bfs(int, int*)': graf.cpp:25: warning: comparison between signed and unsigned integer expressions graf.cpp: In function 'int main()': graf.cpp:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result graf.cpp:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result graf.cpp:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result graf.cpp:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result