Compilare: main.cpp: In function 'int main()': main.cpp:15:87: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("reactivi.in","r",stdin),freopen("reactivi.out","w",stdout),scanf("%d",&n); ^ main.cpp:15:87: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:15:87: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:17:38: 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); ^