SetPoint with a TGraph


I am building a TGraph with the following commands:

   TGraph * grxz = new TGraph();	
   for(int i=0; i<npoints; i++) grxz->SetPoint(i,z[i],x[i]);

I always get an additional point in (0,0). How can I get rid of it?
Thanks in advance,

Looks fine for me. Try:

   TCanvas* can = new TCanvas();
   TGraph* gra = new TGraph();
   for (int i = 0; i < 5; i++) gra->SetPoint(i, i + 1, i + 1);