isnan 和 isinf

#include <math.h>#define isnan(x) _isnan(x)#define isinf(x) (!_finite(x))#define fpu_error(x) (isinf(x) || isnan(x))

int main()

{

double zero=0;double infinite=1/zero;double proper_number=4;printf("isinf(infinite)=%d.\n",isinf(infinite));printf("isinf(proper_number)=%d.\n",isinf(proper_number));printf("isnan(infinite)=%d.\n",isnan(infinite));printf("isnan(proper_number)=%d.\n",isnan(proper_number));double num=-4;double neg_square_root=sqrt(num);printf("isinf(neg_square_root)=%d.\n",isinf(neg_square_root));printf("isinf(proper_number)=%d.\n",isinf(proper_number));printf("isnan(neg_square_root)=%d.\n",isnan(neg_square_root));printf("isnan(proper_number)=%d.\n",isnan(proper_number));

return 0;

}