sqrt, sqrtf, sqrtl

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06/05/2017

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Calculates the square root.

Syntax

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

共用方式為