threads

#include<iostream>
#include<thread>
#include <vector>
using namespace std;

typedef vector<double>::const_iterator ci;
void f(ci begin, ci end, double& zbir);

int main() {
vector<double>v = {10,20,30,40,50};
double zbir1; //ukupan zbir
int n;
cout<<"unesi broj niti: "<<endl;
cin>>n;

ci begin = v.begin();
ci end = v.begin() + (v.size())/n;


thread a[n]; //niz thread-ova
double zbir[n];

//inicijalizacija niza za sume
for(int k=0; k<n;k++) {
    zbir[k] = 0;
    }


for(int j=0; j<n-1; ++j) {
    a[j]= thread(f,begin,end,ref(zbir[j]));
    begin = end;
    end = begin+  ( (v.size())/n );
    zbir1+=zbir[j];
    }
a[n] = thread(f,begin,end,ref(zbir[n-1]));
zbir1+=zbir[n-1];

for(int s=0; s<n; s++) {
    a[s].join();
    }
cout << "ukupno=" << zbir1<< endl;
}

void f(ci begin, ci end, double& zbir){
    ci it;
    for(it=begin; it!=end; ++it) {
        zbir+= *it;
       }

    }