//Fourierova rada - obdelnikove kmity 
#define n 100000  //pocet bodu na 1 otocku
 #define pi 3.1415926535897932384626433832795
 
 double obdelnik(double t,double T)
 {
  double tr;
  double y;
  
  tr=t/T-(int)t/T;
  if(tr<0.5) y=1;
  else y=-1;
  return(y); 
 }
 
 
 int run()
 {
 int i,k;
 double t[n]; //cas
 double f[n]; 
 double y[n]; // casovy krok
 double T=1.0;
 double omega;
 int f_max=10; //pocet uvazovanych clenu Fourirova rozvoje
 double dt;
 
 omega=2.0*pi/T;
 dt=4*T/(double)n; 
 
 
 for(i=0;i<n;i++)
 {
  t[i]=i*dt;
  f[i]=obdelnik(t[i],T);
  y[i]=0.0;
  for(k=1;k<=f_max;k++)y[i]=y[i]+4.0/pi*1.0/(2.0*(double)k-1)*sin((2.0*k-1.0)*omega*t[i]);
   
 }
 
 
 TGraph *gr1 = new TGraph(n,t,f);   //vytvoreni grafu
 TGraph *gr2 = new TGraph(n,t,y);   //vytvoreni grafu
 TCanvas *c1 = new TCanvas("c1","obdelnikove kmity",10,10,600,600); //vytvoreni okna
 gr1->SetMarkerColor(4);  //nastaveni barvy
 gr2->SetMarkerColor(2);  //nastaveni barvy
 gr1->SetLineColor(4);  //nastaveni barvy
 gr2->SetLineColor(2);  //nastaveni barvy 
 gr1->SetTitle("obdelnikove kmity");
 gr1->Draw("AL");         //vykresleni grafu
 gr2->Draw("L");         //vykresleni grafu
 
  
 return(0);
 }