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Compute the absolute value of a double number
#include <math.h>
double fabs( double x );
float fabsf( float x );
- x
- The number you want the absolute value of.
libm
Use the -l m option to
qcc
to link against this library.
These functions compute the absolute value of x.
The absolute value of x.
|
If an error occurs, these functions return 0, but this is also a valid
mathematical result.
If you want to check for errors, set
errno
to 0, call the function, and then check errno again.
These functions don't change errno if no errors occurred. |
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int main( void )
{
printf( "%f %f\n", fabs(.5), fabs(-.5) );
return EXIT_SUCCESS;
}
produces the output:
0.500000 0.500000
ANSI,
POSIX 1003.1
Safety: | |
Cancellation point |
No |
Interrupt handler |
No |
Signal handler |
No |
Thread |
Yes |
abs(),
cabs(),
labs()
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