Compilare: user.cpp: In function ‘double det(double, double)’: user.cpp:26:15: warning: variable ‘yv’ set but not used [-Wunused-but-set-variable] double xv,yv,midv; ^ user.cpp: In function ‘void read()’: user.cpp:13:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:14:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=0;i<=n;i++) scanf("%lf",&a[i]); ^ user.cpp: In function ‘int main()’: user.cpp:40:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radacina.in","r",stdin); ^ user.cpp:41:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radacina.out","w",stdout); ^