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#include <iostream>
#include <vector>
#include <iomanip>
#include <string>
#include <cmath>
#include <algorithm>
#include <limits>

using namespace std;

// declaration of functions
void sieve(int x);
void print(vector<string> str);
int user_input();

string lines = "\n----------------------------------------------------------------------------------------------------\n";

int main(){
    cout << lines << setw(73) <<"Welcome to the Sieve of Eratosthenes Program!" << lines << endl;
    // call the sieve function and ask for user input
    sieve(user_input());
    cout << lines << "Submitted by: Paras, Raymundo, Rosal, and Roxas. :>\n";
    return 0;
}

void sieve(int x){
    // declare vectors to store respected data
    vector<int> table;
    vector<string> marked_table;
    vector<int> prime;
    vector<int> composite;

    // store x values inside the vectors
    for(int i = 1; i <= x; i++){
        table.push_back(i);
        //marked_table.push_back(to_string(i));
    }
    for(int m = 1; m <= x; m++){
        marked_table.push_back("[" + to_string(m) + "]");
    }

    // marking index(0) since 1 is always composite
    replace(marked_table.begin(), marked_table.end(), marked_table.at(0), to_string(1));

    for(int j = 2; j <=  sqrt(x) ; j++){               //loop until j is equals to sqrt(x) times
        if(table.at(j-1)){//if reading element
            for(int k = j; (k * j) <= x; k++){              //iterate until k*j < x
                if( (k * j) % (table.at(j-1)) == 0){  //if remainder none
                    for(int l = 2 ; l <= x; l++){        // loop till it reaches x
                        if(table.at(l-1) == k*j) {// if table element == k*j
                            // then MARK that table element.
                            replace(marked_table.begin(), marked_table.end(), marked_table.at(l - 1), to_string(k * j));
                        }
                        else
                            continue;
                    }
                }
            }
        }
    }
    // call the print function to print table to terminal
    print(marked_table);

    std::sort(composite.begin(), composite.end());
    composite.erase(unique(composite.begin(),composite.end()), composite.end());
    for(auto printcomp : composite){
        cout << printcomp << " ";
    }
    cout << endl << endl;

}

void print(vector<string> str){
    int counter = 0;    //declared a counter for table formatting
    for(auto print : str){  // for each loop to print all elements of the vector
        cout << setfill(' ') << setw(10) << print;  // used IOMANIP library functions to format the table uniformly

        counter++; // iterate counter by 1
        if(counter == 10){  // if counter is equal to 10
            // then linebreak
            cout << endl;
            counter = 0;    // reset counter to 0
        }
    }
}

// function that takes user input
int user_input(){
    //variable to put user's input
    int x;
    cout << "Enter a number: ";
    cin >> x; // store user input
    cout << endl;

    if (cin.fail()) {
        cin.clear(); // Clear the error flag
        cin.ignore(numeric_limits<streamsize>::max(), '\n'); // Discard the input
        cout << "That's not a number. Please input a valid positive number!" << endl;
    }
    else {
        return x;
    }
}