How to fix the Tcanvas in TMultiGraph for several files

[Dosa]

Good day

I am using TMultiGraph to add several plots before drawing them in the same TCanvas and title.
but the problem I got the very different axis limit and overlapped instead of having the axis limit of Canvas and other structures. I will appreciate any help to avoid overlapping of axis and having fixed Canvas for all contain all the plots in it.
I attached the structure of the code

int main()
{
    
    auto  mg  = new TMultiGraph();
    string st = "Pulse";
    string ext = ".txt";
    string filename;
    for (int i=1; i<= 4; i++){
        
	stringstream ss;
        ss << i;
        filename = st + ss.str() + ext;
        cout << filename << "\n";
	
	ifstream myfile(filename.c_str()); 
        for (int j=0; j<60; j++){
            ////////////////
            ///////////////
	    
	TGraph *gr = new TGraphErrors(int,x,y);
	mg->Add(gr,"L");
	}
        
    }
    TCanvas *can = new TCanvas("GRAPH",7000,400);
   gr->SetTitle("Pulse");
    gr->GetXaxis()->SetTitle("Time (s)");
   gr->GetYaxis()->SetTitle(" current"); 
   gr->GetXaxis()->CenterTitle();
    gr->GetXaxis()->SetLimits(1.,1.e8);
    gr->SetMinimum(0.1);
    gr->SetMaximum(1.0);  
        /////////
        ////////
	     
    gStyle->SetTitleFontSize(0.033);   	     	


    mg->Draw("SAME");
    TLegend* legend= new TLegend(0.5,0.7,0.78,0.88);

    legend->AddEntry(gr,"current","l");

    legend->Draw();

    return 0;
    
}

Thank in advance

[Wile_E_Coyote]

TMultiGraph automatically adjusts axes limits according to its added graphs.

You need to: “mg->Draw(); /* creates axes */ gr->Draw(); /* adds another gr */”

BTW. There is no “SAME” drawing option for (multi)graphs.

[Dosa]

yes no, “SAME” was a mistake .
when I use order of :
TGraph *gr = new TGraphErrors(int,x,y);
mg->Add(gr,“L”);
mg->Draw()
axis ////
/////
gr->Draw()
I have got on plot just empty Canvas with no errors comments

[bellenot]

Posting code? Read this first!

This is more addressed to the newer people of this forum, but I think it would be a good refresher for some. USE CODE TAGS!!! What is so special about these things? For one, they help show where you code begins and ends. Plus it doesn’t mess with your spacing or indents (a typical aesthetic in programming). Why do you care so much? When people are communicating code and there is no indentation and lousy spacing, code is super-hard to read. How do I use code tags? The code tag is simple, it…

[Wile_E_Coyote]

@Dosa

no errors comments

Means what?

Make sure that the “gr” is not completely empty, e.g. try: gr->Print();
I don’t think the variable name can be “int” in “TGraphErrors(int,x,y);”

BTW, You added “gr” to “mg” so you do not need to draw “gr” again.

[Dosa]

Yes , on the light of what you said I created the axis then draw gr added all gr then mg->Draw() . also I tried to added gPad->Modified() then axis gPad->Update() but in all cases the axis automatically adjust and gave me the very same chaotic axis . I do not why !
Thanks

[Wile_E_Coyote]

You need to first create the “mg” then add all your “gr” graphs to it and finally draw “mg” (which will then create axes taking into account all its added graphs).

[Dosa]

Exactly that is what I have done then gPad->Update()! but it does not fix the problem

[Wile_E_Coyote]

Check / draw every “gr” graph separately in order to find which one is “bad”.

[Dosa]

it gives me this graph when I’ve checked separately one gr. which the same problem presents

[Wile_E_Coyote]

For a single graph, try: gr->Draw("A*");
For the multigraph, try: mg->Draw("APL");