Using more TCanvas

If I declare more TCanvas and more TGraph, how I can say to a TGraph draw on canvas 1, for example:

    TCanvas *c1 = new TCanvas("c1","canvas 1");
    TCanvas *c2 = new TCanvas("c2","canvas 2");
    TGraph *g1 = new TGraph(n,x1,y1);
    TGraph *g2 = new TGraph(n,x2,y2);

I want to draw g1 on c1 and g2 on c2. I don’t want to switch the declaration.

c1->cd(); g1->Draw("ap"); c2->cd(); g2->Draw("apl");