Extract txt to vector

[nunks]

Hi guys im trying to extract this

1 2 3 4
5 7 8
9 6 10 11
13 14 15 12

into a vector where the blank space can variate and the numbers can switch.How can i get this working?

[Catfish3]

#include <algorithm>
#include <fstream>
#include <iostream>
#include <istream>
#include <iterator>
#include <vector>

std::vector<int> read_numbers(std::istream &is)
{
    int temp;
    std::vector<int> r;

    while (is >> temp)
        r.push_back(temp);

    return r;
}

int main()
{
    std::ifstream input_file("nunks_input.txt");
    std::vector<int> numbers(read_numbers(input_file));

    std::copy(numbers.begin(), numbers.end(), std::ostream_iterator<int>(std::cout, " "));
}