#include <iostream>
#include <cmath>
#include <vector>

using namespace std;

// This program displays all the prime numbers up to a user input

// Remove multiples of an input from the array
void removeMultiples(int input, int limit, vector<bool>& primeList) {
    for (int i = 2; i < (limit / input); ++i) {
        primeList[i * input] = false;
    }
}

int main() {
    cout << "Lists prime numbers up to chosen limit" << endl << endl; // Two endl to leave a space before listing the numbers

    cout << "Please type in a number to use as a limit, then press 'Enter'" << endl;

    int limit;
    cin >> limit;
    cout << endl; // Visually split input number from output list

    vector<bool> primeList(limit);
    primeList.flip();

    for (int i = 2; i < limit; i++) {
        removeMultiples(i, limit, primeList);
    }

    for (int i = 2; i < limit; i++) {
        if (primeList[i] == true)
            cout << i << endl;
    }

    cout << endl << "Press 'Enter' to exit program" << endl;
    cin.ignore(100, '\n'); // ignore any characters in the input buffer until we find an enter character
    cin.get(); // get one more char from the user

    return 0;
}