std::fill_n

template <class OutputIterator, class Size, class T>
  OutputIterator fill_n (OutputIterator first, Size n, const T& val)
{
  while (n>0) {
    *first = val;
    ++first; --n;
  }
  return first;     // since C++11
}

// fill_n example
#include <iostream>     // std::cout
#include <algorithm>    // std::fill_n
#include <vector>       // std::vector

int main () {
  std::vector<int> myvector (8,10);        // myvector: 10 10 10 10 10 10 10 10

  std::fill_n (myvector.begin(),4,20);     // myvector: 20 20 20 20 10 10 10 10
  std::fill_n (myvector.begin()+3,3,33);   // myvector: 20 20 20 33 33 33 10 10

  std::cout << "myvector contains:";
  for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)
    std::cout << ' ' << *it;
  std::cout << '\n';

  return 0;
}