Why does the second while loop in my program not work when there is a while loop before it?

Question

Both of the while loops work individually. However, the second while loop in my code won't work when the while loop above it is present. I need both while loops to work together.

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

int main(){
    string line, line1, line2;
    int count = 0;
    int track = 0;
    int stop;
    ifstream file ("ai.txt");
    while (getline(file, line2)){
        count++;
    }
    file.seekg (0L, ios :: beg);
    stop = count - 10;
    while (getline(file, line)){
        track++;
        if (track >= stop){
            for (int num = 1; num <=10; num++){
                getline(file,line1);
                cout << line1 << endl;   
            }
        }
    }

}

The code should output the last ten lines of any text file.

Lightness Races in Orbit · Accepted Answer · 2019-06-26 23:46:54Z

2

So you consumed all the lines from a file stream.

Then you seeked the stream back to the beginning of the file.

And you started consuming lines again.

What you didn't do is clear the "end of file" flag from the stream that was set when it reached the end the first time. With that flag still in place, the stream's useless.

Add file.clear() before file.seekg(...).

answered Jun 26, 2019 at 23:46

Lightness Races in Orbit

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