Compilare: user.cpp: In function ‘int main()’: user.cpp:19:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ruksak.in","r",stdin); ^ user.cpp:20:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ruksak.out","w",stdout); ^ user.cpp:22:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&g); ^ user.cpp:23:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1;i<=n;++i) scanf("%d%d",&a[i].x,&a[i].y); ^