#include <pthread.h>
#include <iostream>
#include <stdlib.h>
#include <cmath>
double seriesLeibnitz(long start, long endN)
{
    double a = 0.;
    for (int i = start + 1; i <= endN; i++)
		a += (double)(pow(-1, i) / (1 + 2.0 * i));
    return a;
}
double seriesTaylor(long start, long endN)
{
	double a = 0.;
	for (int i = start + 1; i <= endN; i++)
		a += (double)(pow(-1, i) / (i + 2.0));
	return a;
}
struct Data{
    long start;
    long endN;
};
static void *func(void *lpParam)
{
    struct Data dt = *((struct Data *)lpParam);
    double* result = (double*) malloc(sizeof(double));
    *result = seriesTaylor(dt.start, dt.endN);
    return result;
}
int main (int argc, char *argv[])
{
   const int N = 4;
   long iterations = 10000000;
   pthread_t *th = new pthread_t[N];
   Data *dat = new Data[N];
   for (int i = 0; i < N; i++){
        dat[i].start = iterations / N * i;
        dat[i].endN = iterations / N * i  + iterations / N;
        pthread_create(&th[i], NULL, func, &dat[i]);
   }
   double dbl;
   void *t;
   double S = 1;
   for (int i = 0; i < N; i++){
        pthread_join(th[i], (void**)&t);
        dbl = *(double*) t;
        S +=dbl;
   }
   S *= 4;
   std::cout << "Result: " << S << std::endl;
   free(th);
}