cexpf, cexp, cexpl
From cppreference.com
Defined in header
<complex.h>


(1)  (since C99)  
(2)  (since C99)  
(3)  (since C99)  
Defined in header
<tgmath.h>


#define exp( z )

(4)  (since C99) 
13) Computes the complex basee exponential of
z
.
4) Typegeneric macro: If
z
has type long double complex, cexpl
is called. if z
has type double complex, cexp
is called, if z
has type float complex, cexpf
is called. If z
is real or integer, then the macro invokes the corresponding real function (expf, exp, expl). If z
is imaginary, the corresponding complex argument version is called.
Contents 
[edit] Parameters
z    complex argument 
[edit] Return value
If no errors occur, e raised to the power of z
, ez
is returned.
[edit] Error handling and special values
Errors are reported consistent with math_errhandling
If the implementation supports IEEE floatingpoint arithmetic,
 cexp(conj(z)) == conj(cexp(z))
 If
z
is±0+0i
, the result is1+0i
 If
z
isx+∞i
(for any finite x), the result isNaN+NaNi
and FE_INVALID is raised.  If
z
isx+NaNi
(for any finite x), the result isNaN+NaNi
and FE_INVALID may be raised.  If
z
is+∞+0i
, the result is+∞+0i
 If
z
is∞+yi
(for any finite y), the result is+0+cis(y)
 If
z
is+∞+yi
(for any finite nonzero y), the result is+∞+cis(y)
 If
z
is∞+∞i
, the result is±0±0i
(signs are unspecified)  If
z
is+∞+∞i
, the result is±∞+NaNi
and FE_INVALID is raised (the sign of the real part is unspecified)  If
z
is∞+NaNi
, the result is±0±0i
(signs are unspecified)  If
z
is+∞+NaNi
, the result is±∞+NaNi
(the sign of the real part is unspecified)  If
z
isNaN+0i
, the result isNaN+0i
 If
z
isNaN+yi
(for any nonzero y), the result isNaN+NaNi
and FE_INVALID may be raised  If
z
isNaN+NaNi
, the result isNaN+NaNi
where cis(y) is cos(y) + i sin(y)
[edit] Notes
The complex exponential function ez
for z = x+iy equals to ex
cis(y), or, ex
(cos(y) + i sin(y))
The exponential function is an entire function in the complex plane and has no branch cuts.
[edit] Example
Run this code
Output:
exp(i*pi) = 1.0+0.0i
[edit] See also
(C99)(C99)(C99)

computes the complex natural logarithm (function) 
(C99)(C99)

computes e raised to the given power (e^{x}) (function) 
C++ documentation for exp
