Compilare: user.cpp: In function ‘void read(int&)’: user.cpp:23: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp:35: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void bfs(int)’: user.cpp:74: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void bfs(int, int, int&, int&)’: user.cpp:99: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:110: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:111: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result