Newton-Raphson Method to Compute the Square Root in C

#include 
#include 

float square_root(float);

int main(void)
{

 printf("square_root of %f is %f\n", 9.0, square_root(9.0));

 return 0;
}

/*Newton-Raphson Method to Compute the Square Root of x*/
float square_root(float n)
{
 const float epsilon = 0.00001;
 float guess = 1.0;

 while (fabs(guess*guess - n) >= epsilon)
  guess = (n/guess + guess)/2.0;

 return guess;
}