std::exp
From cppreference.com
| Defined in header <cmath>
|
||
| float exp( float arg ); |
(1) | |
| double exp( double arg ); |
(2) | |
| long double exp( long double arg ); |
(3) | |
| double exp( Integral arg ); |
(4) | (since C++11) |
Computes the e (Euler's number, 2.7182818) raised to the given power arg
4) A set of overloads or a function template accepting an argument of any integral type. Equivalent to 2) (the argument is cast to double).
Parameters
| arg | - | value of floating-point or Integral type |
Return value
If no errors occur, the base-e exponential of arg (earg
) 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.
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
Notes
For IEEE-compatible type double, overflow is guaranteed if 709.8 < arg, and underflow is guaranteed if arg < -708.4
Example
Run this code
#include <iostream> #include <cmath> #include <cerrno> #include <cstring> #include <cfenv> #pragma STDC FENV_ACCESS ON int main() { std::cout << "exp(1) = " << std::exp(1) << '\n' << "FV of $100, continuously compounded at 3% for 1 year = " << 100*std::exp(0.03) << '\n'; // special values std::cout << "exp(-0) = " << std::exp(-0.0) << '\n' << "exp(-Inf) = " << std::exp(-INFINITY) << '\n'; // error handling errno=0; std::feclearexcept(FE_ALL_EXCEPT); std::cout << "exp(710) = " << std::exp(710) << '\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:
exp(1) = 2.71828
FV of $100, continuously compounded at 3% for 1 year = 103.045
exp(-0) = 1
exp(-Inf) = 0
exp(710) = inf
errno == ERANGE: Numerical result out of range
FE_OVERFLOW raisedSee also
| (C++11) |
returns 2 raised to the given power (2x) (function) |
| (C++11) |
returns e raised to the given power, minus one (ex-1) (function) |
| computes natural (base e) logarithm (to base e) (ln(x)) (function) | |
| complex base e exponential (function template) | |
| applies the function std::exp to each element of valarray (function template) | |
| C documentation for exp
| |