Make getline only read a few lines at a time C++ 11

so I'm coding a MUD game for a class and I'm trying to figure out how to make getline only read a few lines from the file I'm giving the program at a time. Then when a user selects an option (maybe from a list of switch statements I'm not sure how I'm going to do that yet) it will display the next section of text from the file.

P.S. For reference 3 "~" signifies one block of text at a time. The last while loop I have prints the entire file at once. All I need to do is make getline only read a few lines at once

Thanks for the help!

#include <iostream>
#include <cstdio>
#include <string>
#include <fstream>

using namespace std;

struct Room{
    string name;
    string description;
    int exits[4];
    
};

int main(int argc, char** argv)
{
    //input file stream
    ifstream fin;
    string temp;
    string rooms;
    int count, numRooms;
    
    //checking command line arguments count
    if (argc != 2)
    {
        cout << "Error: Usage, must input only 1 file to read." << endl;
        exit(1);
    }
    
    fin.open(argv[1]);
    
    //checking if file is open.
    if (!fin.is_open())
    {
        cout << "Error: File is not open" << endl;
        return 1;
    }
    
    count = 0;
    //count the ~'s in the file
    while (getline(fin, temp))
    {
        if(temp == "~")
        {
            count++;
        }
    }
    
    numRooms = (count / 3);
    //allocate the memory for the rooms
    Room* room;
    
    room = new Room[numRooms];
    
    //read the room information from file
    
    fin.close();

    ifstream git;

    git.open(argv[1]);

    if (!git.is_open())
    {
        cout << "Error: File is not open" << endl;
        return 1;
    }

    while (getline(git, rooms))
    {
        if (rooms != "~" )
        {
            cout << rooms << endl;
        }
    }
}