Compilare: user.cpp: In function ‘void bfs()’: user.cpp:116:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < v [next . node2] . size () ; ++ i) ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘int getbuff()’: user.cpp:32:44: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread (buff , 1 , BUFF , stdin); ^ user.cpp:42:44: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread (buff , 1 , BUFF , stdin); ^ user.cpp: In function ‘int main()’: user.cpp:140:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen (in , "r" , stdin); ^ user.cpp:141:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread (buff , 1 , BUFF , stdin); ^