Modernise the macro as suggested here...

Modernise the macro as suggested here https://root-forum.cern.ch/t/root-tutorial-chapter-5-3-modifications/29266

documentation/primer/macros/macro7.C

@@ -2,30 +2,31 @@
 // together with its profiles and projections
 
 void macro7(){
-    gStyle->SetPalette(kBird);
-    gStyle->SetOptStat(0);
-    gStyle->SetOptTitle(0);
+   gStyle->SetPalette(kBird);
+   gStyle->SetOptStat(0);
+   gStyle->SetOptTitle(0);
 
-    TH2F bidi_h("bidi_h","2D Histo;Gaussian Vals;Exp. Vals",
-                30,-5,5,  // X axis
-                30,0,10); // Y axis
+   auto bidi_h = new TH2F("bidi_h","2D Histo;Gaussian Vals;Exp. Vals",
+                          30,-5,5,  // X axis
+                          30,0,10); // Y axis
 
-    TRandom3 rgen;
-    for (int i=0;i<500000;i++)
-        bidi_h.Fill(rgen.Gaus(0,2),10-rgen.Exp(4),.1);
+   TRandom3 rgen;
+   for (int i=0;i<500000;i++) {
+      bidi_h->Fill(rgen.Gaus(0,2),10-rgen.Exp(4),.1);
+   }
 
-    auto c=new TCanvas("Canvas","Canvas",800,800);
-    c->Divide(2,2);
-    c->cd(1);bidi_h.DrawClone("Cont1");
-    c->cd(2);bidi_h.DrawClone("Colz");
-    c->cd(3);bidi_h.DrawClone("lego2");
-    c->cd(4);bidi_h.DrawClone("surf3");
+   auto c=new TCanvas("Canvas","Canvas",800,800);
+   c->Divide(2,2);
+   c->cd(1); bidi_h->Draw("Cont1");
+   c->cd(2); bidi_h->Draw("Colz");
+   c->cd(3); bidi_h->Draw("Lego2");
+   c->cd(4); bidi_h->Draw("Surf3");
 
-    // Profiles and Projections
-    auto c2=new TCanvas("Canvas2","Canvas2",800,800);
-    c2->Divide(2,2);
-    c2->cd(1);bidi_h.ProjectionX()->DrawClone();
-    c2->cd(2);bidi_h.ProjectionY()->DrawClone();
-    c2->cd(3);bidi_h.ProfileX()->DrawClone();
-    c2->cd(4);bidi_h.ProfileY()->DrawClone();
+   // Profiles and Projections
+   auto c2=new TCanvas("Canvas2","Canvas2",800,800);
+   c2->Divide(2,2);
+   c2->cd(1); bidi_h->ProjectionX()->Draw();
+   c2->cd(2); bidi_h->ProjectionY()->Draw();
+   c2->cd(3); bidi_h->ProfileX()->Draw();
+   c2->cd(4); bidi_h->ProfileY()->Draw();
 }