std::exp2
From cppreference.com
| Defined in header <cmath>
|
||
| double exp2( double n ); |
(1) | (since C++11) |
| float exp2( float n ); |
(2) | (since C++11) |
| long double exp2( long double n ); |
(3) | (since C++11) |
| double exp2( Integral n ); |
(4) | (since C++11) |
1-3) Computes 2 raised to the given power
n4) A set of overloads or a function template accepting an argument of any integral type. Equivalent to 2) (the argument is cast to double).
Contents |
[edit] Parameters
| n | - | value of floating-point or Integral type |
[edit] Return value
If no errors occur, the base-2 exponential of n (2n
) is returned.
If 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.
[edit] Error handling
Errors are reported as specified in math_errhandling
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
- If the argument is ±0, 1 is returned
- If the argument is -∞, +0 is returned
- If the argument is +∞, +∞ is returned
- If the argument is NaN, NaN is returned
[edit] Example
Run this code
#include <iostream> #include <cmath> #include <cerrno> #include <cstring> #include <cfenv> #pragma STDC FENV_ACCESS ON int main() { std::cout << "exp2(4) = " << std::exp2(4) << '\n' << "exp2(0.5) = " << std::exp2(0.5) << '\n' << "exp2(-4) = " << std::exp2(-4) << '\n'; // special values std::cout << "exp2(-0) = " << std::exp2(-0.0) << '\n' << "exp2(-Inf) = " << std::exp2(-INFINITY) << '\n'; // error handling errno=0; std::feclearexcept(FE_ALL_EXCEPT); std::cout << "exp2(1024) = " << std::exp2(1024) << '\n'; if(errno == ERANGE) std::cout << " errno == ERANGE: " << std::strerror(errno) << '\n'; if(std::fetestexcept(FE_OVERFLOW)) std::cout << " FE_OVERFLOW raised\n"; }
Possible output:
exp2(4) = 16
exp2(0.5) = 1.41421
exp2(-4) = 0.0625
exp2(-0) = 1
exp2(-Inf) = 0
exp2(1024) = inf
errno == ERANGE: Numerical result out of range
FE_OVERFLOW raised[edit] See also
| returns e raised to the given power (ex) (function) | |
| (C++11) |
returns e raised to the given power, minus one (ex-1) (function) |
| (C++11) |
base 2 logarithm of the given number (log2(x)) (function) |
| C documentation for exp2
| |