Compilare: user.cpp: In function ‘int main()’: user.cpp:33:15: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(f2>p2)if(ok==2&&mx<(f2-p2)*(p1-f1)){mx=(f2-p2)*(p1-f1);} ^ user.cpp:12:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen("cabana2.in","r",stdin); ^ user.cpp:13:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cabana2.out","w",stdout); ^ user.cpp:14:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:16:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a[i].x,&a[i].y); ^