Compilare: user.cpp: In function ‘int main()’: user.cpp:24:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("aria.in","r",stdin); ^ user.cpp:25:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("aria.out","w",stdout); ^ user.cpp:26:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:31:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&a[i].x,&a[i].y); ^ user.cpp:44:21: warning: ‘ind’ may be used uninitialized in this function [-Wmaybe-uninitialized] swap(a[1],a[ind]); ^