STL algorithm算法fill(14)_stl algorithm fill-优快云博客

本文链接：https://blog.youkuaiyun.com/qq844352155/article/details/39204861

本文详细介绍了C++中std::fill函数的用法，包括其参数、行为、返回值和复杂度等内容。通过示例代码展示了如何使用该函数将指定范围内的元素填充为特定值。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

原文地址：http://www.cplusplus.com/reference/algorithm/fill/

function template

 
 <algorithm> 

std::fill

template <class ForwardIterator, class T>
  void fill (ForwardIterator first, ForwardIterator last, const T& val);

Fill range with value

Assigns val to all the elements in the range [first,last). 使用val填满范围内的元素。

例子：

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

void fill2(){
    vector<int> vi{1,5,7,8,9,9,8,5,9};
    cout<<"at first,vi=";
    for(int &i:vi)
        cout<<i<<" ";
    cout<<endl;

    fill(vi.begin(),vi.end()-3,1000);
     cout<<"after     fill(vi.begin(),vi.end()-3,1000),\nvi=";
    for(int &i:vi)
        cout<<i<<" ";
    cout<<endl;

}

运行截图：

The behavior of this function template is equivalent to:

template <class ForwardIterator, class T>
  void fill (ForwardIterator first, ForwardIterator last, const T& val)
{
  while (first != last) {
    *first = val;
    ++first;
  }
}

Parameters

first, last

Forward iterators to the initial and final positions in a sequence of elements that support being assigned a value of type T. The range filled is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
要填充的范围。

val

Value to assign to the elements in the filled range.
填充的值。

Return value

none

Example

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

int main () {
  std::vector<int> myvector (8);                       // myvector: 0 0 0 0 0 0 0 0

  std::fill (myvector.begin(),myvector.begin()+4,5);   // myvector: 5 5 5 5 0 0 0 0
  std::fill (myvector.begin()+3,myvector.end()-2,8);   // myvector: 5 5 5 8 8 8 0 0

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

  return 0;
}