sqrt(), sqrtf(), sqrtl() — Calculate square root
Standards
Standards / Extensions | C or C++ | Dependencies |
---|---|---|
ISO C |
both |
Format
#include <math.h>
double sqrt(double x);
float sqrt(float x); /* C++ only */
long double sqrt(long double x); /* C++ only */
float sqrtf(float x);
long double sqrtl(long double x);
General description
Calculates the square
root of x.
Note: These functions work in
both IEEE Binary Floating-Point and hexadecimal floating-point formats.
See IEEE binary floating-point for more information
about IEEE Binary Floating-Point.
Returned value
If successful, returns the square root of x.
If x is negative, the function sets errno to EDOM, and returns 0. If the correct value would cause underflow, zero is returned and the value ERANGE is stored in errno.
Special behavior for IEEE
If x< -0, the function returns NaNQ and sets errno to EDOM.
If x is a NaN, a NaN will be returned.
If x is ±0 or +INF, x will be returned.
If x is -INF, a EDOM will be set, and NaNQ will be returned.
Example
CELEBS30
/* CELEBS30
This example computes the square root of the quantity passed
as the first argument to main.
It prints an error message if you pass a negative value.
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main(int argc, char ** argv)
{
char * rest;
double value;
if ( argc != 2 )
printf( "Usage: %s value\n", argv[0] );
else
{
value = strtod( argv[1], &rest );
if ( value < 0.0 )
printf( "sqrt of a negative number\n" );
else
printf("sqrt( %f ) = %f\n", value, sqrt( value ));
}
}
Output
If the input is 45, then
the output should be:
sqrt( 45.000000 ) = 6.708204