auto canvas = new TCanvas();
gStyle->SetPalette(kBird, 0, 0.6); // define a transparent palette

const int n = 100;
double x[n];
double y[n];
double c[n];
double s[n];

auto r  = new TRandom();
for (int i=0; i<n; i++) {
   x[i] = 100*r->Rndm(i);
   y[i] = 200*r->Rndm(i);
   c[i] = 300*r->Rndm(i);
   s[i] = 400*r->Rndm(i);
}

auto scatter = new TScatter(n, x, y, c, s);
scatter->SetMarkerStyle(20);
scatter->SetTitle("Scatter plot;X;Y");
scatter->Draw("A");

gROOT->GetListOfCanvases()->Draw()