Defined in header <math.h> | ||
|---|---|---|
float exp2f( float n ); | (1) | (since C99) |
double exp2( double n ); | (2) | (since C99) |
long double exp2l( long double n ); | (3) | (since C99) |
Defined in header <tgmath.h> | ||
#define exp2( n ) | (4) | (since C99) |
n.n has type long double, exp2l is called. Otherwise, if n has integer type or the type double, exp2 is called. Otherwise, exp2f is called.| n | - | floating point 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.
Errors are reported as specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
#include <stdio.h>
#include <math.h>
#include <float.h>
#include <errno.h>
#include <fenv.h>
// #pragma STDC FENV_ACCESS ON
int main(void)
{
printf("exp2(5) = %f\n", exp2(5));
printf("exp2(0.5) = %f\n", exp2(0.5));
printf("exp2(-4) = %f\n", exp2(-4));
// special values
printf("exp2(-0.9) = %f\n", exp2(-0.9));
printf("exp2(-Inf) = %f\n", exp2(-INFINITY));
//error handling
errno = 0; feclearexcept(FE_ALL_EXCEPT);
printf("exp2(1024) = %f\n", exp2(1024));
if(errno == ERANGE) perror(" errno == ERANGE");
if(fetestexcept(FE_OVERFLOW)) puts(" FE_OVERFLOW raised");
}Possible output:
exp2(5) = 32.000000
exp2(0.5) = 1.414214
exp2(-4) = 0.062500
exp2(-0.9) = 0.535887
exp2(-Inf) = 0.000000
exp2(1024) = Inf
errno == ERANGE: Result too large
FE_OVERFLOW raised|
(C99)(C99) | computes e raised to the given power (\({\small e^x}\)ex) (function) |
|
(C99)(C99)(C99) | computes e raised to the given power, minus one (\({\small e^x-1}\)ex-1) (function) |
|
(C99)(C99)(C99) | computes base-2 logarithm (\({\small \log_{2}{x} }\)log2(x)) (function) |
C++ documentation for exp2 |
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