Compilare: user.cpp: In function ‘int main()’: user.cpp:51:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qtri.in","r",stdin); ^ user.cpp:52:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qtri.out","w",stdout); ^ user.cpp:54:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:57:72: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d%d%d",&tx,&ty,&tx2,&ty2,&tx3,&ty3,&tx4,&ty4); ^