/* A C program to calculate the distance between two points */
/*                                                          */
/* compile this with:                                       */
/*    gcc -lm -o dist dist.c                                */

#include <stdio.h>
#include <math.h>

int main (void)
{
  double x1=2.0, y1=4.0;
  double x2=5.0, y2=8.0;
  double dx, dy;
  double d, d_sq;

  dx = x2 - x1;
  dy = y2 - y1;

  d_sq = dx*dx + dy*dy;
  d = sqrt(d_sq);

  printf("%f\n", d);
  return 0;
}