Compilare: user.cpp: In function ‘void input()’: user.cpp:37:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &n ) ; ^ user.cpp:40:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &a[ i ].first , &a[ i ].second ) ; ^ user.cpp: In function ‘int main()’: user.cpp:87:41: 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:88:43: 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 ) ; ^