fill in C++ STL

The ‘fill’ function assigns the value ‘val’ to all the elements in the range [begin, end), where ‘begin’ is the initial position and ‘end’ is the last position. NOTE : Notice carefully that ‘begin’ is included in the range but ‘end’ is NOT included. Below is an example to demonstrate ‘fill’ : 

CPP

// C++ program to demonstrate working of fill()
#include <bits/stdc++.h>
using namespace std;

int main()
{
    vector<int> vect(8);

    // calling fill to initialize values in the
    // range to 4
    fill(vect.begin() + 2, vect.end() - 1, 4);

    for (int i = 0; i < vect.size(); i++)
        cout << vect[i] << " ";

    return 0;
}

Output:

0 0 4 4 4 4 4 0

We can also use fill to fill values in an array. 

CPP

// C++ program to demonstrate working of fill()
#include <bits/stdc++.h>
using namespace std;

int main()
{
    int arr[10];

    // calling fill to initialize values in the
    // range to 4
    fill(arr, arr + 10, 4);

    for (int i = 0; i < 10; i++)
        cout << arr[i] << " ";

    return 0;
}

Output:

4 4 4 4 4 4 4 4 4 4

Filling list in C++. 

CPP

// C++ program to demonstrate working of fill()
#include <bits/stdc++.h>
using namespace std;

int main()
{
    list<int> ml = { 10, 20, 30 };

    fill(ml.begin(), ml.end(), 4);

    for (int x : ml)
        cout << x << " ";

    return 0;
}

Output:

4 4 4

The time complexity of fill function: O(N)