title: Finding the Distance Between Two Points in C
body: <p>I want to calculate the distance between two points but I need to do it by using a main function. I am having some difficulties in trying to make sure that my program returns the correct value. I have attached my code to this so I would appreciate it if anyone can help in correcting the portion that I may have made a mistake. 
  (Note: I am fairly new to C so I may need some additional help in understanding some things.) </p>
  
  <pre><code>#include &lt;stdio.h&gt;
  double distance(double x1, double y1, double x2, double y2)
  {
      double square_difference_x = (x2 - x1) * (x2 - x1);
      double square_difference_y = (y2 - y1) * (y2 - y1);
      double sum = square_difference_x + square_difference_y;
      double z = 0.00001;
      for (double i = 0; i &lt; sum; i = i + z)
      {
          if (i * i == sum)
          {
              return i;
          }
      }
  }
  
  int main(void)
  {
      double a = 1.0, b = 2.0, c = 4.0, d = 6.0;
      double dis;
      dis = distance(a, b, c, d);
      printf("The distance of the points (%lf, %lf) and (%lf, %lf) is %lf\n",  a,b,c,d,dis);
  
      return 0;
  }
  </code></pre>
  
  <p>I feel like my problem is happening with the <code>return</code> option in the main function although I am not so sure how to fix this problem if there is one. 
  `</p>