Compilare: user.cpp: In function ‘int main()’: user.cpp:15:40: 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:16:42: 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:18:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d " , &q ); ^ user.cpp:21:91: 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" , &x1 , &y1 , &x2 , &y2 , &x3 , &y3 , &x4 , &y4 ); ^