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



double func(double x);
double calka(double a, double b, int N);


int main(int argc, char *argv[])
{
    int a, N;

    a=0;
    double b = M_PI;

    printf("POdaj dokladnosc N ");
    scanf("%d", &N);

    printf("\n Calka wynosi: %.151f \n", calka(a,b,N));
}

    double calka(double a, double b, int N){

        double suma = 0.0;
        double i, x1 = a, x2;
        double dx = (b-a)/N;
        double f1, f2, temp;
        double c = 0.5 * dx;
        temp = func(x1);

        for(i =0; i<N;i++){
            x2 = x1+dx;
            f1 = temp;
            temp = f2 = func(x2);
            suma += c*(f1 + f2);

            x1=x2;
        }
        return suma;
    }


    double func(double x){
        double sinus = sin(x);
        return sinus;
    }