# include <math.h>

float my_sqrt ( float s )
{
  float e;
  int i;
  float r1;
  float r2;

  r1 = 1.0;

  for ( i = 0; i < 10; i++ )
  {
    r2 = s / r1;
    e = fabs ( s - r1 * r1 );
    if ( e < 0.0000001 )
    {
      break;
    }
    r1 = ( r1 + r2 ) / 2;
  }

  return r1;
}