#include <iostream> #include <cmath> int main(void) { std::cout << "copysign(1.0,+2.0) = " << std::copysign(1.0,+2.0) << '\n' << "copysign(1.0,-2.0) = " << std::copysign(1.0,-2.0) << '\n' << "copysign(inf,-2.0) = " << std::copysign(INFINITY,-2.0) << '\n...
std::copysign是操作NaN值%28的符号以检查NaN符号的唯一可移植方式,signbit也可以使用%29。 例 二次 代码语言:javascript 复制 #include <iostream> #include <cmath> int main(void) { std::cout << "copysign(1.0,+2.0) = " << std::copysign(1.0,+2.0) << '\n' << "copysign(1.0,-2.0) = ...
std::copysign,std::copysignf,std::copysignl C++ Numerics library Common mathematical functions Defined in header<cmath> (1) floatcopysign(floatmag,floatsgn); doublecopysign(doublemag,doublesgn); longdoublecopysign(longdoublemag,longdoublesgn); ...
此函数检测零、无穷大和 NaN 的符号。 std::signbit 是检验 NaN 符号的唯二可移植方式,另一方式是std::copysign。 示例 运行此代码 #include <iostream>#include <cmath>intmain(){std::cout<<std::boolalpha<<"signbit(+0.0) = "<<std::signbit(+0.0)<<'\n'<<"signbit(-0.0) = "<<std::sign...
double modf(double num, double* iptr) { #pragma STDC FENV_ACCESS ON int save_round = std::fegetround(); std::fesetround(FE_TOWARDZERO); *iptr = std::nearbyint(num); std::fesetround(save_round); return std::copysign(std::isinf(num) ? 0.0 : x - (*iptr), num); }...
std::signbit 是检验 NaN 正负号的唯二可移植方式,另一方式是 std::copysign。 额外重载不需要以 (A) 的形式提供。它们只需要能够对它们的整数类型实参 num 确保std::signbit(num) 和std::signbit(static_cast<double>(num)) 的效果相同。 示例运行此代码 #include <cmath> #include <iostream> int ...
std::copysign std::cos std::cos(std::complex) std::cos(std::valarray) std::cosh std::cosh(std::complex) std::cosh(std::valarray) std::cyl_bessel_i std::cyl_bessel_if std::cyl_bessel_il std::cyl_bessel_j std::cyl_bessel_jf std::cyl_bessel_jl std::cyl_bessel_k std::cyl_...
#include <cfenv>#include <cmath>#pragma STDC FENV_ACCESS ONdoubleround(doublex){constintsave_round=std::fegetround();std::fesetround(FE_TOWARDZERO);constdoubleresult=std::rint(std::copysign(0.5+std::fabs(x), x));std::fesetround(save_round);returnresult;} ...
std::copysign std::cos std::cos(std::complex) std::cos(std::valarray) std::cosh std::cosh(std::complex) std::cosh(std::valarray) std::cyl_bessel_i std::cyl_bessel_if std::cyl_bessel_il std::cyl_bessel_j std::cyl_bessel_jf std::cyl_bessel_jl std::cyl_bessel_k std::cyl_...
std::copysign std::cos std::cos(std::complex) std::cos(std::valarray) std::cosh std::cosh(std::complex) std::cosh(std::valarray) std::cyl_bessel_i std::cyl_bessel_if std::cyl_bessel_il std::cyl_bessel_j std::cyl_bessel_jf std::cyl_bessel_jl std::cyl_bessel_k std::cyl_...