#include <stdio.h>
#include <stdlib.h>
#include <math.h>
double f(double x)
{
    return sin(x);
}

int main()
{
    int N;
    printf("Specify N: ");
    scanf("%i",&N);

    double h;
    h = M_PI/N;

    double sum = 0;

    double x;
    x=h;

    for(int i=0;i<=N;i++)
    {
        if (i==0)
        {
            sum+=f(0)/2;
        }
        if (i==N)
        {
            sum+=f(M_PI)/2;
        }
        else
        {
            sum+=f(x);
            x+=h;
        }
    }

    double result = h*sum;
    printf("The Trapezoid method result for %i is %.10lf",N,result);

    return 0;
}