pow(3C)
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pow $builtin function
Raise the first argument to the power of the second argument.
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Calling Sequence
double m, n, o, pow();
m = pow(n,o);
(or)
$builtin double pow();
double m, n, o;
m = pow(n,o);
where m, n, and o are of type double.
Description
Use the pow function to return the value of one argument raised
to the power of another. With pow, m is the result of raising n
to the power o.
The first version of the calling sequence above uses a function
call. The second might generate smaller or faster code, but may
not run under other C compilers.
The include file math.h defines this entry and uses the $builtin
version.
Returns
If floating-point overflow or underflow occurs, this function
returns the largest possible floating-point number and sets errno
to ERANGE (defined in errno.h).
Related Functions
See also the exp function.
Example
/* Program test for the pow() function */
#include <math.h>
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pow(3C)
int i = 2;
double m, n, o, atof(), pow();
main(argc, argv)
int argc;
char *argv[];
{
n = atof(argv[1]);
while (i < argc) {
o = atof(argv[i]);
printf("%f\tto the power %f = %f\n", n, o,
m = pow(n, o));
i++;
}
}
A call to the program test with the number 1.999999 followed by
the numbers 10, 5, 2.5, 1.25, and 0.625 generates the output
1.999999 to the power 10.000000 = 1023.994880
1.999999 to the power 5.000000 = 31.999920
1.999999 to the power 2.500000 = 5.656847
1.999999 to the power 1.250000 = 2.378413
1.999999 to the power 0.625000 = 1.542210
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