C++

Reference

<cmath> (math.h)

function
<cmath> <ctgmath>

sqrt

double sqrt (double x);
     double sqrt  (double x);      float sqrtf (float x);long double sqrtl (long double x);
     double sqrt (double x);      float sqrt (float x);long double sqrt (long double x);
     double sqrt (double x);      float sqrt (float x);long double sqrt (long double x);     double sqrt (T x);           // additional overloads for integral types
Compute square root
Returns the square root of x.

Header <tgmath.h> provides a type-generic macro version of this function.
This function is overloaded in <complex> and <valarray> (see complex sqrt and valarray sqrt).
Additional overloads are provided in this header (<cmath>) for the integral types: These overloads effectively cast x to a double before calculations (defined for T being any integral type).

This function is also overloaded in <complex> and <valarray> (see complex sqrt and valarray sqrt).

Parameters

x
Value whose square root is computed.
If the argument is negative, a domain error occurs.

Return Value

Square root of x.
If x is negative, a domain error occurs:

If a domain error occurs, the global variable errno is set to EDOM.
If a domain error occurs:
- And math_errhandling has MATH_ERRNO set: the global variable errno is set to EDOM.
- And math_errhandling has MATH_ERREXCEPT set: FE_INVALID is raised.

Example

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/* sqrt example */
#include <stdio.h>      /* printf */
#include <math.h>       /* sqrt */

int main ()
{
  double param, result;
  param = 1024.0;
  result = sqrt (param);
  printf ("sqrt(%f) = %f\n", param, result );
  return 0;
}

Output:

sqrt(1024.000000) = 32.000000


See also

pow
Raise to power (function)
log
Compute natural logarithm (function)