Compilare: user.cpp: In function ‘int main()’: user.cpp:58:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in","r",stdin); ^ user.cpp:59:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out","w",stdout); ^ user.cpp:60:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:63:48: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&domino[i].x,&domino[i].y); ^ user.cpp: In function ‘void euler(int)’: user.cpp:27:24: warning: ‘i’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (domino[i].x!=v) vecin=domino[i].x,backk=0; ^