exp, expf, expl
Defined in header <math.h>
|
||
---|---|---|
|
(1) | (since C99) |
|
(2) | |
|
(3) | (since C99) |
Defined in header <tgmath.h>
|
||
|
(4) | (since C99) |
1-3) Computes the e (Euler's number, 2.7182818
) raised to the given power arg
.
4) Type-generic macro: If arg
has type long double
, expl
is called. Otherwise, if arg
has integer type or the type double
, exp
is called. Otherwise, expf
is called. If arg
is complex or imaginary, then the macro invokes the corresponding complex function (cexpf
, cexp
, cexpl
).
Parameters
arg | - | floating point value |
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
#include <stdio.h>
#include <math.h>
#include <float.h>
#include <errno.h>
#include <fenv.h>
#pragma STDC FENV_ACCESS ON
int main(void)
{
printf("exp(1) = %f\n", exp(1));
printf("FV of $100, continuously compounded at 3%% for 1 year = %f\n",
100*exp(0.03));
// special values
printf("exp(-0) = %f\n", exp(-0.0));
printf("exp(-Inf) = %f\n", exp(-INFINITY));
//error handling
errno = 0; feclearexcept(FE_ALL_EXCEPT);
printf("exp(710) = %f\n", exp(710));
if(errno == ERANGE) perror(" errno == ERANGE");
if(fetestexcept(FE_OVERFLOW)) puts(" FE_OVERFLOW raised");
}
Possible output:
exp(1) = 2.718282
FV of $100, continuously compounded at 3% for 1 year = 103.045453
exp(-0) = 1.000000
exp(-Inf) = 0.000000
exp(710) = inf
errno == ERANGE: Numerical result out of range
FE_OVERFLOW raised
References
C11 standard (ISO/IEC 9899:2011):
- 7.12.6.1 The exp functions (p: 242)
- 7.25 Type-generic math (p: 373-375)
- F.10.3.1 The exp functions (p: 520)
C99 standard (ISO/IEC 9899:1999):
- 7.12.6.1 The exp functions (p: 223)
- 7.22 Type-generic math (p: 335-337)
- F.9.3.1 The exp functions (p: 458)
C89/C90 standard (ISO/IEC 9899:1990):
- 4.5.4.1 The exp function
See also
(C99)(C99)(C99) |
computes 2 raised to the given power (2x) (function) |
(C99)(C99)(C99) |
computes e raised to the given power, minus one (ex-1) (function) |
(C99)(C99) |
computes natural (base-e) logarithm (ln(x)) (function) |
(C99)(C99)(C99) |
computes the complex base-e exponential (function) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/c/numeric/math/exp