C++ Lab3 SortString

#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <string>
#include <cmath>
#include <algorithm>
#include <regex>
using namespace std;
enum Order { ASCENDING, DESCENDING };

class AutoSortedWordList {
public:
    AutoSortedWordList();
    void setWord(string word, int index);
    void setOrderOption(Order order);
    void print();
private:
    const static int NUM_WORD = 5;
    string list[NUM_WORD];
    Order order;

    void sort();
    //void swap(int i, int j);
};

AutoSortedWordList::AutoSortedWordList(){
    setOrderOption(ASCENDING);
}

void AutoSortedWordList::setOrderOption(Order order) {
    AutoSortedWordList::order = order;
    sort();
}

void AutoSortedWordList::setWord(string word, int index) {
    if (index >= 0 && index < NUM_WORD) {
        list[index] = word;
        cout << "Add \"" << word << "\" at the index " << index << endl;
    }
    else
        cout << "Cannot add word: index out of range!!!\n\n\n";
    sort();
}

void AutoSortedWordList::print() {
    cout << "All words in list: " << endl;
    for (int i = 0; i < NUM_WORD; i++)
        cout << "\t" << list[i] << endl;
}

void AutoSortedWordList::sort() {
    int counter = 0;
    for (int index = 0; index < NUM_WORD; index++) {
        if (list[index] != "\0")
            counter++;
    }

    //int N = sizeof(list) / sizeof(list[0]);
    std::sort(list, list+counter);
    if (AutoSortedWordList::order == DESCENDING) {
        std::reverse(list, list+counter);
    }

}

int main() {
    AutoSortedWordList aWordList;

    aWordList.setWord("Hello", 0);
    aWordList.setWord("Konnichiwa", 1);
    aWordList.setWord("Hallo", 2);
    cout << "\n\n ASCENDING 3" << endl;
    aWordList.print();

    aWordList.setWord("Ciao", 3);
    cout << "\n\n ASCENDING 4" << endl;
    aWordList.print();

    aWordList.setWord("Ni hao", 4);
    aWordList.setWord("alo", 5);

    cout << "\n\nDefault : ASCENDING ORDER" << endl;
    aWordList.print();

    cout << "\n\nDECESDING ORDER" << endl;
    aWordList.setOrderOption(DESCENDING);
    aWordList.print();

    system("pause");
    return 0;
}