Compilare: user.cpp: In member function ‘void Circle::read()’: user.cpp:34:16: warning: unused variable ‘_x’ [-Wunused-variable] double _x=x,_y=y; ^ user.cpp:34:21: warning: unused variable ‘_y’ [-Wunused-variable] double _x=x,_y=y; ^ user.cpp: In function ‘int main()’: user.cpp:124:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cerc.in","r",stdin); ^ user.cpp:125:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cerc.out","w",stdout); ^ user.cpp:127:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp: In member function ‘void Circle::read()’: user.cpp:31:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf%lf",&x,&y,&R); ^