Use new PbrResults struct for PBR results

src/PbrDialog.vala

@@ -94,17 +94,17 @@ public class Balistica.PbrDialog : Gtk.Dialog {
     */
    [GtkCallback]
    public void btnCalculate_clicked() {
-	  double pbr_results[4] = LibBalistica.PBR.pbr (d,
-													double.parse (drag_coeff.get_text ()),
-													double.parse (initial_vel.get_text ()),
-													double.parse (sight_height.get_text ()),
-													double.parse (vital_zone_sz.get_text ())) ;
-
-	  results.buffer.text = "Near Zero: " + pbr_results[0].to_string () + " yards\n" ;
-	  results.buffer.text += "Far Zero: " + pbr_results[1].to_string () + " yards\n" ;
-	  results.buffer.text += "Minimum PBR: " + pbr_results[2].to_string () + " yards\n" ;
-	  results.buffer.text += "Maximum PBR: " + pbr_results[3].to_string () + " yards\n\n" ;
-	  results.buffer.text += "Sight-in at 100 yards: " + pbr_results[4].to_string () + " inches high" ;
+	  LibBalistica.PbrResult pbr_result = LibBalistica.PBR.pbr (d,
+																double.parse (drag_coeff.get_text ()),
+																double.parse (initial_vel.get_text ()),
+																double.parse (sight_height.get_text ()),
+																double.parse (vital_zone_sz.get_text ())) ;
+
+	  results.buffer.text = "Near Zero: %.2f yards\n".printf (pbr_result.near_zero) ;
+	  results.buffer.text += "Far Zero: %.2f yards\n".printf (pbr_result.far_zero) ;
+	  results.buffer.text += "Minimum PBR: %.2f yards\n".printf (pbr_result.min_pbr) ;
+	  results.buffer.text += "Maximum PBR: %.2f yards\n\n".printf (pbr_result.max_pbr) ;
+	  results.buffer.text += "Sight-in at 100 yards: %.2f inches high".printf (pbr_result.sight_in_height) ;
    }
 
 }

src/libbalistica/libbalistica.vala

@@ -58,6 +58,17 @@ namespace LibBalistica{
 	  public double vertical_velocity ;
    }
 
+   /**
+    * Return value for a PBR optimization results
+    */
+   public struct PbrResult {
+	  public double near_zero ;
+	  public double far_zero ;
+	  public double min_pbr ;
+	  public double max_pbr ;
+	  public double sight_in_height ;
+   }
+
 /**
  * The different drag functions you are allowed to pick from
  */

src/libbalistica/pbr.vala

@@ -36,11 +36,11 @@ namespace LibBalistica{
 	   *				  must remain in, e.g. the point impact must always be within a
 	   *				  two inch diameter circle.
 	   *
-	   * @return An array of 5 doubles consisting of the near zero, far zero, min pbr,
-	   *				  max pbr, and sight-in height at 100 yards.
+	   * @return A LibBalistica.PbrResult struct containing our five results.
 	   */
-	  public static double[] pbr(DragFunction Drag, double DragCoefficient, double Vi, double SightHeight, double VitalSize) {
-		 double result[4] ;
+	  public static LibBalistica.PbrResult pbr(DragFunction Drag, double DragCoefficient, double Vi, double SightHeight, double VitalSize) {
+		 LibBalistica.PbrResult result = LibBalistica.PbrResult () ;
+
 		 double t = 0 ;
 		 double dt = 0.5 / Vi ;
 		 double v = 0 ;
@@ -170,16 +170,12 @@ namespace LibBalistica{
 			}
 		 }
 
-		 // Near zero
-		 result[0] = zero / 3 ;
-		 // Far zero
-		 result[1] = farzero / 3 ;
-		 // Minimum PBR
-		 result[2] = min_pbr_range / 3 ;
-		 // Maximum PBR
-		 result[3] = max_pbr_range / 3 ;
-		 // Sight-in at 100 yards (in 100ths of an inch)
-		 result[4] = tin100 ;
+		 result.near_zero = zero / 3 ;
+		 result.far_zero = farzero / 3 ;
+		 result.min_pbr = min_pbr_range / 3 ;
+		 result.max_pbr = max_pbr_range / 3 ;
+		 // At 100 yards (in 100ths of an inch)
+		 result.sight_in_height = tin100 ;
 
 		 return result ;
 	  }