#include <iostream>



using namespace std;


double single(double *x, double *par) {
    return pow(sin(pi*par[0]*x[0])/(pi*par[0]*x[0]),2);
}

double nslit0(double *x, double *par){
    return pow(sin(pi*par[1]*x[0])/sin(pi*x[0]),2);
}

doublle nslit(double *x, double *par){
    return single(x,par)*nslit0(x,par);
}

void slits(){
    float r,ns;

    cout<<"slit width /g ? ";
    scanf("%f", &r);
    cout<<"# of slits? ";
    scanf("%f", &ns);

    cout<<"interference pattern for "<<ns
        <<" slits, width/distance: "<<r<<endl;


    TF1 *Fnslit = new TF1("Fnslit", nslit,-5.001,5.,2);
    Fnslit-> SetNpx(500);


    Fnslit->SetParameter(0,r);
    Fnslit->SetParameter(1,ns);

    Fnslit->Draw();

}