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#include<iostream>
bool is_zero(const double &d)
{
if (d)
{
return false;
}
else
{
return true;
}
}
int main()
{
double dval1 = 0;
double dval2 = 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001;
std::cout << "zero or not? " << is_zero(dval2) << std::endl;
return 0;
}
...
#define DBL_DIG 15 /* # of decimal digits of precision */
#define DBL_EPSILON 2.2204460492503131e-016 /* smallest such that 1.0+DBL_EPSILON != 1.0 */
#define DBL_MANT_DIG 53 /* # of bits in mantissa */
#define DBL_MAX 1.7976931348623158e+308 /* max value */
#define DBL_MAX_10_EXP 308 /* max decimal exponent */
#define DBL_MAX_EXP 1024 /* max binary exponent */
#define DBL_MIN 2.2250738585072014e-308 /* min positive value */
#define DBL_MIN_10_EXP (-307) /* min decimal exponent */
#define DBL_MIN_EXP (-1021) /* min binary exponent */
#define _DBL_RADIX 2 /* exponent radix */
#define _DBL_ROUNDS 1 /* addition rounding: near */
...
#include <float.h>
#include <math.h>
...
if (fabs(d)<DBL_EPSILON)