From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/c/numeric%2Fmath%2Fexp2.html | 77 ++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 devdocs/c/numeric%2Fmath%2Fexp2.html (limited to 'devdocs/c/numeric%2Fmath%2Fexp2.html') diff --git a/devdocs/c/numeric%2Fmath%2Fexp2.html b/devdocs/c/numeric%2Fmath%2Fexp2.html new file mode 100644 index 00000000..66fa43ca --- /dev/null +++ b/devdocs/c/numeric%2Fmath%2Fexp2.html @@ -0,0 +1,77 @@ +

exp2, exp2f, exp2l

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)
+1-3) Computes 2 raised to the given power n.
+4) Type-generic macro: If 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.

Parameters

+ +
n - floating point value

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.

+

Error handling

Errors are reported as specified in math_errhandling.

+

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

+

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("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

References

See also

+ + + +
+
(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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Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
+ https://en.cppreference.com/w/c/numeric/math/exp2 +

+
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