#include <iostream>
    #include <math.h>
    #include <stdlib.h>
    #include <stdio.h>

    using namespace std;

    // Erstellt einen Pointer einen double Wert!
    typedef double (*func)(double);

    // Die verwendete Funktion
    double f(double x){
    return sin(x);
    }
    double g(double x)
    {
        return x*x;
    }


    double trapez (double a, double b,int n,int antin,func f)
    {
        double ergebnis=0;
        double h;
        double ueberpruefer;
        double antih;


        h = (b-a)/n;

        for (int i = 1; i <=n; i++) {
            ergebnis += f(a+h*(2*i-1)/2);
        }
        ergebnis*=h;

        // Anti Ergebniss
        antih= (b-a)/antin;

        for (int x = 1; x <=antin; x++) {
            ueberpruefer+= f(a+antih*(2*x-1)/2);
        }
        ueberpruefer*=antih;

        if (fabs((ueberpruefer-ergebnis)/ergebnis)>=0.000001) {

            n=n*2;
            antin=antin*2;
            cout << antin << endl;



            ueberpruefer= trapez(a,b,n,antin,f);

        }

        return ueberpruefer;
    }

    double integral (double a, double b, int n,func f)
    {


        double h= (b-a)/n;

        double x;
        double qf;

        double sum;

        qf=f(a)+f(b);

        sum=0.;
        for (int k =1; k <=n-1; k++) {
            x=a+k*h;
            sum+=f(x);

        }

        qf+=2*sum;

        sum=0;

        for (int k=1; k<=n; k++) {

            x=((a+(k-1)*h)+(a+k*h))/2;

            sum+=f(x);

        }
        qf+=4*sum;

        return qf*h/6;

    }

    double* faltungsintegral(double a,double b, int n,func f,func g){
           double ergebniss=0;
            double qf=0;
            double h;
            int k,i=0;
            double *ary;
            ary = (double*)malloc(10000*sizeof(double));
            h=(b-a)/n;

            for(double t = a; t<=b; t=t+h){

            qf=(f(a)*g(a-t))+(f(b)*g(b-t));
            for(k=1;k<n;k++){
                    qf+=2*((f(a+(h*k)))*(g(a+(h*k)-t)));
            }
            //cout << qf<< endl;
            for(k=1;k<=n;k++){

                    qf+=4*((f(((a+h*k)+(a+(h*(k-1))))/2))*(g(-t+((a+h*k)+(a+(h*(k-1))))/2)));

            }
            //cout << qf << endl;

                ergebniss = (qf * h)/6;
                ary[i]=ergebniss;
               i++;
            }
       //     for (int tau = 0; tau<n;tau++){
        //        printf("%lf\n", ary[tau]);
        //    }

            return ary;
        }



     int main()
        {
            double* d ;
            double a=0;
            double b=2;
            double n=20;

           // double h = (b-a)/n;
    /*
        for(double t = a; t<=b;t=t+h){
            arrays[arraystelle]=faltungsintegral(a,b,n,arraystelle,t,&g,&g);
            arraystelle++;
        }
        cout << arrays[0] << endl;
    */

        d=faltungsintegral(a,b,n,&f,&g) ;
        for (int tau = 0; tau<=n;tau++){
                cout << d[tau] << endl;
            }

              //  for (int x=0; x<=10;x++){
                 //   cout << d << endl;
                //}

            free(d);
            return 0;
        }