typedef struct {double v; double e;} double_error;

double_error convert_int(int);

double_error to_exptype(double);

bool is_greater(double_error,double_error);

double_error maximum(double_error,double_error);

double_error sum(double_error,double_error);

double_error difference(double_error,double_error);

double_error product(double_error,double_error);

double_error ratio(double_error,double_error);

double_error absolute(double_error);

double_error power(double_error,double_error);

double to_double(double_error);

bool to_string(char*,double_error);

bool root_to_string(char*,double_error,double_error);