#include <time.h>

void macro_ex() {
 


 TCanvas *c1 = new TCanvas("c1","A Simple Graph Example",200,10,700,500);

   c1->SetFillColor(42);
   c1->SetGrid();
   
   TStopwatch sw; 
   sw.Start();
    
   const Int_t max = 10;
   
  
   Double_t x[max];
   Double_t y[max];
  
   Double_t c=0;
   x[0]=0;
   y[0]=0;

   gr = new TGraph(1,x, y);
   gr->SetMarkerStyle(21);
   gr->SetTitle("Time graph");
   gr->GetXaxis()->SetTitle("X title");
   gr->GetYaxis()->SetTitle("Y title");
   c1->Update();
   c1->Clear();
   Int_t i =0;
   while(1){

                sw.Stop();
		c=sw.RealTime();
		
		sw.Continue();
    	
		x[i] = c;
 
		if (i%2 == 0)  // only to draw triangles
		  y[i] = 2000;
		else
	          y[i] = 2;
     		
		gr->SetPoint(i,x[i],y[i]);
     
     	 	gr->Draw("AL");
     	 	c1->Update();
     		gSystem->Sleep(1000);
                i= i+1;
		
		if (i==max)
	          i=0;
   }
 
}