Losowanie z pliku

#include <iostream>
#include <fstream>
#include <string>
#include <time.h>
#include <stdlib.h>
using namespace std;

int main ()
{
    int number_of_lines = 0;
    string line;
    ifstream myfile("abc.txt");

    if(!myfile.is_open()) return 0;
    while(getline(myfile, line)) number_of_lines++;
    srand(time(NULL));
    int rand_val = rand() % number_of_lines + 1;
    myfile.clear();
    myfile.seekg (0, myfile.beg);
    for(int i = 0; i < rand_val; i++) getline(myfile, line);
    cout << line << endl;
    return 0;
}