Int_t i;
const Int_t nx = 20;
const char *people[nx] = {"Jean","Pierre","Marie","Odile",
   "Sebastien","Fons","Rene","Nicolas","Xavier","Greg",
   "Bjarne","Anton","Otto","Eddy","Peter","Pasha",
   "Philippe","Suzanne","Jeff","Valery"};
TCanvas *c1 = new TCanvas("c1","demo bin labels",10,10,900,500);
c1->SetGrid();
c1->SetBottomMargin(0.15);
TH1F *h = new TH1F("h","test",nx,0,nx);
h->SetFillColor(38);
for (i=0;i<5000;i++) h->Fill(gRandom->Gaus(0.5*nx,0.2*nx));
h->SetStats(0);
for (i=1;i<=nx;i++) h->GetXaxis()->SetBinLabel(i,people[i-1]);
h->Draw();
TPaveText *pt = new TPaveText(0.6,0.7,0.98,0.98,"brNDC");
pt->SetFillColor(18);
pt->SetTextAlign(12);
pt->AddText("Use the axis Context Menu LabelsOption");
pt->AddText(" \"a\"   to sort by alphabetic order");
pt->AddText(" \">\"   to sort by decreasing values");
pt->AddText(" \"<\"   to sort by increasing values");
pt->Draw();

gROOT->GetListOfCanvases()->Draw()