sqrt, sqrtf

Article
2013-02-01

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 
);

Parameters

x
Nonnegative floating-point value

Remarks

C++ allows overloading, so users 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 function returns the square-root of x. If x is negative, sqrt returns an indefinite, by default.

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

Requirements

Routine	Required header
sqrt, sqrtf	<math.h>

For additional compatibility information, see Compatibility in the Introduction.

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 %.2f\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

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