Compilare: user.cpp: In function ‘void init()’: user.cpp:21:35: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(F,sizeof(char),lg,stdin); ^ user.cpp: In function ‘int main()’: user.cpp:80:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("dijkstra.in","r",stdin); ^ user.cpp:81:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("dijkstra.out","w",stdout); ^