LazyUpdate reference example

git-svn-id: svn://ultimatepp.org/upp/trunk@968 f0d560ea-af0d-0410-9eb7-867de7ffcac7

reference/LazyUpdate/LazyUpdate.cpp

@@ -0,0 +1,35 @@
+#include <Core/Core.h>
+
+using namespace Upp;
+
+struct DblSum {
+	Vector<double> d;
+	mutable double sum;
+	LazyUpdate dirty;
+
+public:
+	void Add(double x) {
+		d.Add(x);
+		dirty.Invalidate();
+	}
+
+	double Sum() const {
+		if(dirty.BeginUpdate()) {
+			Vector<int> o = GetSortOrder(d);
+			sum = 0;
+			for(int i = 0; i < o.GetCount(); i++)
+				sum += d[o[i]];
+			dirty.EndUpdate();
+		}
+		return sum;
+	}
+};
+
+CONSOLE_APP_MAIN
+{
+	DblSum x;
+	x.Add(100);
+	for(int i = 0; i < 1000*1000; i++)
+		x.Add(1e-10);
+	Cout() << x.Sum() << "\n";
+}

reference/LazyUpdate/LazyUpdate.upp

@@ -0,0 +1,10 @@
+uses
+	Core;
+
+file
+	LazyUpdate.cpp;
+
+mainconfig
+	"" = "",
+	"" = "MT";
+

reference/LazyUpdate/init

@@ -0,0 +1,4 @@
+#ifndef _LazyUpdate_icpp_init_stub
+#define _LazyUpdate_icpp_init_stub
+#include "Core/init"
+#endif