Compilare: user.cpp: In function ‘int main()’: user.cpp:218:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "bile4.in" , "r", stdin ); ^ user.cpp:219:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "bile4.out", "w", stdout ); ^ user.cpp:223:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d", &N, &M ); ^ user.cpp:225:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d %d %d", &X, &Y, &Z, &T ); ^