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/*************************************************
Distance between points

Write a program that readsin two points (x1,y1)
and (x2,y2) and prints out the distance between
the two points.  Write and use a function
distance(x1,y1,x2,y2) to help you do this.

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

double distance(double x1, double y1, double x2, double y2);

int main() {
  // Get coordinates
  double x1;
  double y1;
  printf("Enter point 1: ");
  fflush(stdout);
  scanf(" ( %lg , %lg )", &x1, &y1);

  double x2;
  double y2;
  printf("Enter point 2: ");
  fflush(stdout);
  scanf(" ( %lg , %lg )", &x2, &y2);

  // Write distance
  printf("The distance between points is %g\n",
         distance(x1,y1,x2,y2));

  return 0;
}

/***********************************
 ** distance between two points
 ***********************************/
double distance(double x1, double y1, double x2, double y2) {
  double X = x1 - x2;
  double Y = y1 - y2;
  return sqrt(X*X + Y*Y);
}