Reading From Files

[IamANoob21]

!!!!

[MaseratiDeluxe]

11111

[MiiNiPaa]

If you have two sorted sequences it is job for merge: https://en.wikipedia.org/wiki/Merge_algorithm

The general merge algorithm has a set of pointers p0..n that point to positions in a set of lists L0..n. Initially they point to the first item in each list. The algorithm is as follows:

While any of p0..n still point to data inside of L0..n instead of past the end:

1) do something with the data items p0..n point to in their respective lists
2) find out which of those pointers points to the item with the lowest key; advance one of those pointers to the next item in its list

Also look at this: http://en.cppreference.com/w/cpp/algorithm/merge
It comes with reference imlementations you can stydy and try to understand.

An example of merging two input streams in one output:

#include <algorithm>
#include <iostream>
#include <iterator>
#include <sstream>

int main()
{
    std::istringstream f1 {"1 4 5 18"};
    std::istringstream f2 {"2 3 15 16"};
    std::ostringstream out;
    std::merge(std::istream_iterator<int>(f1), std::istream_iterator<int>(),
               std::istream_iterator<int>(f2), std::istream_iterator<int>(),
               std::ostream_iterator<int>(out, ", "));
    std::cout << out.str();
}

http://coliru.stacked-crooked.com/a/fd71f0d173ccf36a

I cheated a little and made input values to be separated by space, but it is not that hard to make stream to threat comma as space too.