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| Nearest integer floating point operations | |||||||||||||||||||||||||||||||||||||||||
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| Floating point manipulation functions | |||||||||||||||||||||||||||||||||||||||||
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Defined in header <cmath> | ||
| (1) | ||
float pow(float base,float exp); double pow(double base,double exp); | (until C++23) | |
/* floating-point-type */ pow(/* floating-point-type */ base, | (since C++23) (constexpr since C++26) | |
float pow(float base,int exp); double pow(double base,int exp); | (2) | (until C++11) |
float powf(float base,float exp); | (3) | (since C++11) (constexpr since C++26) |
longdouble powl(longdouble base,longdouble exp); | (4) | (since C++11) (constexpr since C++26) |
Additional overloads(since C++11) | ||
Defined in header <cmath> | ||
template<class Arithmetic1,class Arithmetic2> /* common-floating-point-type */ | (A) | (constexpr since C++26) |
std::pow for all cv-unqualified floating-point types as the type of the parametersbase andexp.(since C++23)A) Additional overloads are provided for all other combinations of arithmetic types. | (since C++11) |
Contents |
| base | - | base as a floating-point or integer value |
| exp | - | exponent as a floating-point or integer value |
If no errors occur,base raised to the power ofexp (baseexp
), is returned.
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a pole error or a range error due to overflow occurs,±HUGE_VAL,±HUGE_VALF, or±HUGE_VALL is returned.
If a range error occurs due to underflow, the correct result (after rounding) is returned.
Errors are reported as specified inmath_errhandling.
Ifbase is finite and negative andexp is finite and non-integer, a domain error occurs and a range error may occur.
Ifbase is zero andexp is zero, a domain error may occur.
Ifbase is zero andexp is negative, a domain error or a pole error may occur.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
|base| < 1.|base| > 1.|base| < 1.|base| > 1.C++98 added overloads whereexp has typeint on top of Cpow(), and the return type ofstd::pow(float,int) wasfloat. However, the additional overloads introduced in C++11 specify thatstd::pow(float,int) should returndouble.LWG issue 550 was raised to target this conflict, and the resolution is to removed the extraintexp overloads.
Althoughstd::pow cannot be used to obtain a root of a negative number,std::cbrt is provided for the common case whereexp is 1/3.
The additional overloads are not required to be provided exactly as(A). They only need to be sufficient to ensure that for their first argumentnum1 and second argumentnum2:
| (until C++23) |
Ifnum1 andnum2 have arithmetic types, thenstd::pow(num1, num2) has the same effect asstd::pow(static_cast</*common-floating-point-type*/>(num1), If no such floating-point type with the greatest rank and subrank exists, thenoverload resolution does not result in a usable candidate from the overloads provided. | (since C++23) |
#include <cerrno>#include <cfenv>#include <cmath>#include <cstring>#include <iostream>// #pragma STDC FENV_ACCESS ON int main(){// typical usagestd::cout<<"pow(2, 10) = "<< std::pow(2,10)<<'\n'<<"pow(2, 0.5) = "<< std::pow(2,0.5)<<'\n'<<"pow(-2, -3) = "<< std::pow(-2,-3)<<'\n'; // special valuesstd::cout<<"pow(-1, NAN) = "<< std::pow(-1,NAN)<<'\n'<<"pow(+1, NAN) = "<< std::pow(+1,NAN)<<'\n'<<"pow(INFINITY, 2) = "<< std::pow(INFINITY,2)<<'\n'<<"pow(INFINITY, -1) = "<< std::pow(INFINITY,-1)<<'\n'; // error handlingerrno=0;std::feclearexcept(FE_ALL_EXCEPT); std::cout<<"pow(-1, 1/3) = "<< std::pow(-1,1.0/3)<<'\n';if(errno==EDOM)std::cout<<" errno == EDOM "<<std::strerror(errno)<<'\n';if(std::fetestexcept(FE_INVALID))std::cout<<" FE_INVALID raised\n"; std::feclearexcept(FE_ALL_EXCEPT); std::cout<<"pow(-0, -3) = "<< std::pow(-0.0,-3)<<'\n';if(std::fetestexcept(FE_DIVBYZERO))std::cout<<" FE_DIVBYZERO raised\n";}
Possible output:
pow(2, 10) = 1024pow(2, 0.5) = 1.41421pow(-2, -3) = -0.125pow(-1, NAN) = nanpow(+1, NAN) = 1pow(INFINITY, 2) = infpow(INFINITY, -1) = 0pow(-1, 1/3) = -nan errno == EDOM Numerical argument out of domain FE_INVALID raisedpow(-0, -3) = -inf FE_DIVBYZERO raised
(C++11)(C++11) | computes square root (\(\small{\sqrt{x}}\)√x) (function)[edit] |
(C++11)(C++11)(C++11) | computes cube root (\(\small{\sqrt[3]{x}}\)3√x) (function)[edit] |
(C++11)(C++11)(C++11) | computes hypotenuse\(\scriptsize{\sqrt{x^2+y^2}}\)√x2 +y2 and\(\scriptsize{\sqrt{x^2+y^2+z^2}}\)√x2 +y2 +z2 (since C++17) (function)[edit] |
| complex power, one or both arguments may be a complex number (function template)[edit] | |
| applies the functionstd::pow to two valarrays or a valarray and a value (function template)[edit] | |
C documentation forpow | |
