Insertion and Deletion in list <string> - c++

Question

I am currently writing a small program to insert or delete a row in a list of string read from an input text file.
This is my code
#include <vector>
#include <string>
#include <sstream>
#include <iostream>
#include <fstream>
#include <list>
using namespace std;
int main()
{
list <string> buffer;
string fileName = "input.txt";
ifstream file(fileName);
if (file.is_open())
{
string line;
while (getline(file, line))
{
//store each line in the buffer
buffer.push_back(line);
}
}
list<string>::const_iterator it;
it = buffer.begin();
int position = 1;
for (int n = 0; n < position; ++n)
{
++it;
}
string input("This is a new line");
buffer.insert(it, 1, input);
//I can then use erase function to delete a line
system("pause");
return 0;
}
The buffer list has
This is line 1
This is line 2
This is line 3
This is line 4
I want to know if there are other ways (maybe more efficient) to insert or delete a line in the buffer. Thank you!

Answer 1

There are several versions of list<>::insert(). One of them inserts a single element, so you can replace this:
buffer.insert(it, 1, input);
with:
buffer.insert(it, input);
You can also use list<>::emplace() to create the string in place :
buffer.emplace(it, "This is a new line");
You can simplify this:
list<string>::const_iterator it;
it = buffer.begin();
int position = 1;
for (int n = 0; n < position; ++n)
{
++it;
}
to:
auto it = buffer.begin();
advance(it, 1);