FINAL Working QS with menu

#include "pch.h"
#include <iostream>
#include <cstdlib>
#include "time.h"

using namespace std;

int arrSize;
int *arr;

int deli(int dno, int vrh);
void izpisiZaporedje();
void hitroUredi(int dno, int vrh);
void generirajNakljucno();
void generirajNarascajoce();
void generirajPadajoce();
void preveri(int dno, int vrh);
void definirajZaporedje();

int main()
{
    clock_t start, finish;
    double duration;
    srand(time(NULL));

    while (true) {

    int izbira;
    cout <<
        "Hitro uredi - izbira\n\n" <<
        "1 Generiraj nakljucno zaporedje\n" <<
        "2 Generiraj urejeno narascajoce zaporedje\n" <<
        "3 Generiraj urejeno padajoče zaporedje\n" <<
        "4 Izpis zaporedja\n" <<
        "5 Uredi\n" <<
        "6 Konec\n" <<
        "Vasa izbira: ";
    cin >> izbira;
    cout << endl;

    switch (izbira) {
        case 1:
            definirajZaporedje();
            generirajNakljucno();
            break;
        case 2:
            definirajZaporedje();
            generirajNarascajoce();
            break;
        case 3:
            definirajZaporedje();
            generirajPadajoce();
            break;
        case 4:
            izpisiZaporedje();
            break;
        case 5:
            start = clock();
            hitroUredi(0, arrSize - 1);
            finish = clock();
            duration = (double)(finish - start);
            cout << "Cas izvajanja: " << duration << endl;
            preveri(0, arrSize - 1);
            break;
        case 6:
            return 1;
        default:
            cout << "Vpisi ponovno: ";
        }
    cout << "------------------------" << endl;
    }

}

void definirajZaporedje() {
    int size;
    cout << "Vnesi dolzino zaporedja: ";
    cin >> size;

    arrSize = size;

    int a = size;
    arr = new int[a];
}

void preveri(int dno, int vrh) {
    bool pravilnoUrejeno = true;
    for (int i = dno; i < vrh - 1; i++) {
        if (arr[i + 1] < arr[i]) {
            cout << arr[i + 1] << " " << arr[i] << endl;
            pravilnoUrejeno = false;
        }
    }
    if (pravilnoUrejeno) cout << "Zaporedje je pravilno urejeno" << endl << endl;
    else cout << "Zaporedje ni pravilno urejeno" << endl << endl;
}


void generirajNakljucno() {
    for (int i = 0; i < arrSize; i++)
        arr[i] = (rand() % 50000);
}

void generirajNarascajoce() {
    for (int i = 0; i < arrSize; i++)
        arr[i] = i;
}

void generirajPadajoce() {
    for (int i = arrSize; i >= 0; i--)
        arr[i] = arrSize - i;
}

void hitroUredi(int dno, int vrh) {
    if (dno < vrh) {
        int j = deli(dno, vrh);
        hitroUredi(dno, j - 1);
        hitroUredi(j + 1, vrh);
    }
}

int deli(int dno, int vrh) {

    int m = (dno + vrh) / 2;

    int tmpA = arr[dno];
    arr[dno] = arr[m];
    arr[m] = tmpA;

    int pe = arr[dno];
    int levi = dno + 1;
    int desni = vrh;

    while (true) {

        while (arr[levi] < pe && levi <= vrh) levi++;
        while (arr[desni] > pe && desni >= dno) desni--;

        if (desni <= levi) break;
        else {
            int tmpB = arr[levi];
            arr[levi] = arr[desni];
            arr[desni] = tmpB;
            levi++;
            desni--;
        }
    }

    int tmpC = arr[dno];
    arr[dno] = arr[desni];
    arr[desni] = tmpC;

    return desni;
}

void izpisiZaporedje() {
    for (int i = 0; i < arrSize; i++) {
        cout << arr[i] << " ";
    }
    cout << endl <<endl;
}