求大神指导 c程序编写数组求平均数

#include<iostream>
#include<iterator>
#include<vector>
#include<numeric>
#include<algorithm>
using namespace std;
int main(){
vector<int> v;
copy(istream_iterator<int>(cin), istream_iterator<int>(), back_inserter(v));
cout << accumulate(v.begin(), v.end(), 0) / v.size() << endl;
return 0;
}