update to std::sort

tin.h

@@ -11,6 +11,7 @@
 #define _TIN_DELAUNAY_H
 #include "cmath"
 #include "vector"
+#include "algorithm"
 
 #define ZERO 1e-5
 
@@ -22,8 +23,8 @@ struct vertex2dc
 	double elev; // elevation at the vertex
 
 	vertex2dc() : x(NAN), y(NAN), elev(NAN), id(0) {}
-	vertex2dc(double inx, double iny, double inelev, unsigned int inid = 0) {set(inx, iny, inelev, inid);}
-	void set(double inx, double iny, double inelev, unsigned int inid = 0)
+	vertex2dc(double inx, double iny, double inelev, unsigned int inid) {set(inx, iny, inelev, inid);}
+	void set(double inx, double iny, double inelev, unsigned int inid)
 	{
 		x = inx; y = iny; elev = inelev; id = inid;
 		return;
@@ -131,7 +132,7 @@ struct dem_point
 {
 	double x, y; // position of the DEM location
 	double elev; // elevation at the DEM location
-	double err;
+	double err; // error of the TIN with respect to the elevation 
 	triangle *host; // host triangle of the DEM location
 	std::vector<triangle*> circum_host; // triangles which circumcircles include the location
 
@@ -144,55 +145,10 @@ struct dem_point
 	}
 };
 
-/**
- * @brief      Utility function of the heap_sort function.
- *
- * @param      a     Input vector
- * @param[in]  i     vector's index i
- * @param[in]  n     vector's index n
- */
-void update_heap(std::vector<dem_point*> &a, int i, int n)
+bool compare_dem_point(dem_point *a, dem_point *b)
 {
-	int iMax = i, iLeft = 2 * i + 1, iRight = 2 * (i + 1);
-
-	if (iLeft < n && a[iMax]->err > a[iLeft]->err)
-	{
-		iMax = iLeft;
-	}
-
-	if (iRight < n && a[iMax]->err > a[iRight]->err)
-	{
-		iMax = iRight;
-	}
-
-	if (iMax != i)
-	{
-		dem_point *tmp = a[iMax]; a[iMax] = a[i]; a[i] = tmp;
-		update_heap(a, iMax, n);
-	}
-	return;
-}
-
-/**
- * @brief      Heap sort of the dem_point vector in a descending order with respect to the error values
- *
- * @param      a     Input vector
- */
-void heap_sort(std::vector<dem_point*> &a)
-{
-	int n = a.size();
-	for (int i = (n - 1) / 2; i >= 0; i--)
-	{
-		update_heap(a, i, n);
-	}
-
-	dem_point *tmp;
-	for (int i = n - 1; i > 0; --i)
-	{
-		tmp = a[i]; a[i] = a[0]; a[0] = tmp;
-		update_heap(a, 0, i);
-	}
-	return;
+	if (a->err > b->err) return true;
+	return false;
 }
 // End DEM definition
 
@@ -228,7 +184,7 @@ void dem2tin(const std::vector<double> &dem, double xmin, double xmax, double ym
 	if (dem.size() != xnum*ynum) return;
 
 	// Prepare the DEM points
-	dem_point *tmp_dem;
+	dem_point *tmp_dem = nullptr;;
 	std::vector<dem_point*> dem_grid(xnum*ynum);
 	std::vector<dem_point*>::iterator d_iter;
 	for (int i = 0; i < ynum; ++i)
@@ -240,7 +196,6 @@ void dem2tin(const std::vector<double> &dem, double xmin, double xmax, double ym
 	}
 
 	vertex2dc *tmp_vert = nullptr;
-
 	tmp_vert = new vertex2dc(xmin, ymin, dem_grid[0]->elev, out_verts.size()); // lower left corner
 	out_verts.push_back(tmp_vert);
 
@@ -320,7 +275,8 @@ void dem2tin(const std::vector<double> &dem, double xmin, double xmax, double ym
 		dem_grid[i]->err = fabs(dem_grid[i]->host->interpolate(dem_grid[i]->x, dem_grid[i]->y) - dem_grid[i]->elev);
 	}
 
-	heap_sort(dem_grid);
+	// Sort dem_grid in the desceding order with respect to the error
+	std::sort(dem_grid.begin(), dem_grid.end(), compare_dem_point);
 
 	bool removed;
 	edge tmp_edge;
@@ -457,7 +413,8 @@ void dem2tin(const std::vector<double> &dem, double xmin, double xmax, double ym
 			delete tmp_tri; tmp_tri = nullptr;
 		}
 
-		heap_sort(dem_grid);
+		// Sort dem_grid in the desceding order with respect to the error
+		std::sort(dem_grid.begin(), dem_grid.end(), compare_dem_point);
 	}
 
 	if (err_records != nullptr)