How to change the color of the background of histogram?

[meixue]

I want to change the color of one part of a histogram to highlight this part, like the red one. How should I do?

[couet]

void highlighthist() {
   auto h1 = new TH1F("h1", "h1", 100, -5., 5.) ; h1->FillRandom("gaus", 10000);
   auto h2 = (TH1F*)h1->Clone();
   h2->SetFillColor(kBlue-3);

   h1->Draw();
   h2->GetXaxis()->SetRangeUser(0, 1);
   h2->Draw("SAME");
}

[meixue]

Thankyou! But I prefer to set the whole histogram of this part to another color like this picture

[couet]

To obtain the last picture you sent, simply draw a TBox on top of your histogram.

[meixue]

How do I set any color in this plot?

[dastudillo]

kRed+1 etc.