void histo()
{
int N = 50;// počet bodů
double prob = 0.8;// pravdepodobnosť kroku v pravo
double x[100];
FILE* file = fopen("data.txt","w");
TRandom3* rand = new TRandom3(0);
TGraph* graph = new TGraph(N);// konstruktor bodového grafu s N body
TH1D* hist = new TH1D("hist","Histogram krokov",100,0,50);
TF1* fNorm = new TF1("fNorm","gaus",0,50);
for (int k = 0; k < 1000; k++){
int a = 0;
int b = 0;
for (int i = 0; i < N; i++){
x[i] = rand -> Rndm();
if(x[i]>prob){
  a=a+1;
  graph->SetPoint(i, i, a);  
}else{
  a=a-1;
  b=b+1;
  graph->SetPoint(i, i, a);
}
}
hist->Fill(b);
fprintf(file,"%f\n",b);
}
hist->Draw();
fNorm->SetParameter(0,125);
fNorm->SetParameter(1,(prob*100)/2);
fNorm->SetParameter(2,3);
fNorm->SetLineColor(4);
fNorm->Draw("Same");

fclose(file);
/*
graph->SetTitle("");
graph->GetXaxis()->SetTitle("x");
graph->GetYaxis()->SetTitle("y");
graph->SetMarkerStyle(2);
graph->Draw("AC*");// PA
*/
}