Compilare: user.cpp: In function ‘int main()’: user.cpp:27:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "pipe.in" , "r" , stdin ); ^ user.cpp:28:62: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d %d %d %d\n" , &n , &x1 , &y1 , &x2 , &y2 ); ^ user.cpp:32:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%c" , &c ); ^ user.cpp:33:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] if (c=='A') scanf ( "%d\n" , &A[a++] ); ^ user.cpp:34:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] else scanf ( "%d\n" , &R[r++] ); ^ user.cpp:43:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "pipe.out" , "w" , stdout ); ^