TGraphErrors *graph = new TGraphErrors(n,x,y,ex,ey); graph->SetMarkerSize(2);
TGraphErrors *graph = new TGraphErrors(n,x,y,ex,ey); Double_t markerSize = 0.5; graph->SetMarkerSize(markerSize);In this example, a TGraphErrors object is created again with n points, where x and y are arrays of the x and y coordinates respectively, and ex and ey are arrays of the error bars in the x and y directions respectively. The SetMarkerSize function is also used to set the size of the markers in the graph, but this time a Double_t variable markerSize is used to specify the marker size. The value of markerSize is set to 0.5.