// simplified chapter1_1.c using Point structure
//
#include <stdio.h>
#include <math.h>

// a point in 2 dimensions
//
typedef struct { double x, y; } Point;

double pythag( double a, double b)
{
  return sqrt( a*a + b*b);
}

double distance( Point p, Point q)
{
  return pythag( p.x - q.x, p.y - q.y);
}

int main(void)
{
   Point p = { 1.1, 5.5 }, q = { 4.4, 7.7 };

   double d = distance( p, q);

   printf( "d = %g\n", d);

   return 0;
}