Compilare: user.cpp: In function ‘int main()’: user.cpp:57:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( FILE_IN, "r", stdin ); ^ user.cpp:58:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( FILE_OUT, "w", stdout ); ^ user.cpp:62:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:66:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%Lf %Lf %Lf %Lf", &a, &b, &x0, &y0); ^ user.cpp:80:4: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (x > y) ^