sqrt, sqrtf, sqrtl

Calculates the square root.

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 
);

Parameters

x
Non-negative floating-point value

Remarks

Because C++ allows overloading, you can call overloads of sqrt that take float or long double types. In a C program, sqrt always takes and returns double.

Return Value

The sqrt functions return the square-root of x. By default, if x is negative, sqrt returns an indefinite NaN.

Input	SEH Exception	_matherr Exception
± QNAN,IND	none	_DOMAIN
- ∞	none	_DOMAIN
x<0	none	_DOMAIN

Requirements

Function	C header	C++ header
sqrt, sqrtf, sqrtl	<math.h>	<cmath>

For compatibility information, see Compatibility.

Example

// crt_sqrt.c
// This program calculates a square root.

#include <math.h>
#include <stdio.h>
#include <stdlib.h>

int main( void )
{
   double question = 45.35, answer;
   answer = sqrt( question );
   if( question < 0 )
      printf( "Error: sqrt returns %f\n", answer );
   else
      printf( "The square root of %.2f is %.2f\n", question, answer );
}

The square root of 45.35 is 6.73

.NET Framework Equivalent

System::Math::Sqrt