c++ fill 和fill_n

 template < class ForwardIterator, class T >

  void fill ( ForwardIterator first, ForwardIterator last, const T& value );

Fill range with value

Sets value to all elements in the range [first,last).

fill_n函数模板如下：

template < class OutputIterator, class Size, class T >
  void fill_n ( OutputIterator first, Size n, const T& value );

Fill sequence with value

Sets value to the first n elements in the sequence pointed by first.

fill_n不检查是否有足够的空间来填充，切记使用是保证有足够的空间，不然会导致disaster。

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

int main()
{
    vector<int> vec(10);
    fill_n(vec.begin(),10,1);
    for(int i=0;i<vec.size();i++)
        cout<<vec[i]<<ends;
    fill(vec.begin(),vec.end(),2);
    for(int i=0;i<vec.size();i++)
        cout<<vec[i]<<ends;

    cout<<endl;
}