# include <stdio.h>

float fran ( float a, float b, int *seed );

int main ( )
{
  int hits;
  int i;
  int n = 100;
  int seed = 123;
//
// #1: what more declarations must we add here?
//
  hits = 0;
  for ( i = 0; i < n; i++ )
  {
    x = fran ( -1.0, +1.0, &seed );
    y = fran ( -1.0, +1.0, &seed );
//
//  #2: Fill in the "condition" in the following IF statement:
//
//  An IF statement has the form 
//
//    if ( condition )
//
//  You need to write an arithmetic statement about x and y that is
//  true if the point (x,y) is inside a circle of radius 1.
//  If you have trouble with this, please ask Detelina for advice!
//
    if (    (x,y) is inside the circle    )
    {
      hits = hits + 1;
    }
  }
//
//  #3: Compute the estimate, the exact area, and the error.
//
  area_estimate = number of hits divided by total number of tries 

  area_exact = formula for the area of a circle of radius 1

  error = | estimate - exact |     <-- how do we take the absolute value?
//
//  #4: Print your result.
//
  print n, estimate, exact, and error here.

  return 0;
}



float fran ( float a, float b, int *seed )
//
//  Purpose:
//
//    FRAN returns a scaled pseudorandom float between A and B.
//
//  Parameters:
//
//    Input, float A, B, the limits of the interval.
//
//    Input/output, int *SEED, the "seed" value, which should NOT be 0.
//    On output, SEED has been updated.
//
//    Output, float FRAN, a number between A and B.
//
{
  int i4_huge = 2147483647;
  int k;
  float value;
//
//  Check SEED.
//
  if ( *seed == 0 )
  {
    printf ( "\n" );
    printf ( "FRAN - Fatal error!\n" );
    printf ( "  Input value of SEED = 0.\n" );
    exit ( 1 );
  }
//
//  Update SEED.
//
  k = *seed / 127773;

  *seed = 16807 * ( *seed - k * 127773 ) - k * 2836;

  if ( *seed < 0 )
  {
    *seed = *seed + i4_huge;
  }
//
//  Convert SEED to a real number in [0,1].
//
  value = ( float ) ( *seed ) * 4.656612875E-10;
//
//  Scale to a real number in [A,B].
//
  value = a + ( b - a ) * value;

  return value;
}