sort list

#include "stdafx.h"
#include <iostream>
using namespace std;

struct elem
{
    int key;
    elem *next;
}*start;


void init();
void add(int n);
void print_list();
void sort();

void main()
{
    init();
    cout << "Vavedete chisla za spisaka (0 za kraj): " << endl;
    int number;

    while (true)
    {
        cin >> number;

        if (number == 0)
        {
            break;
        }

        add(number);
    }

    sort();
    print_list();
}

void init()
{
    start = NULL;
}

void add(int n)
{
    elem *p = start, *q;
    q = new elem;
    q->key = n;
    q->next = NULL;
    if (start)
    {
        while (p->next)
            p = p->next;
        p->next = q;
    }
    else
    {
        start = q;
    }
}

void print_list()
{
    elem *p = start;

    if (start)
    {
        cout << "Elementite na spisaka sa: \n";

        while (p)
        {
            if (p->key != NULL) {
                cout << p->key << "\t";
            }
            p = p->next;
        }
        cout << endl;
    }
    else
        cout << "Nqma elementi v spisaka.";
}

void sort()
{
    elem *p1 = start;

    while (p1 != NULL)
    {
        elem *p2 = p1;

        while (p2 != NULL)
        {
            if (p1->key > p2->key)
            {
                int swap = p1->key;
                p1->key = p2->key;
                p2->key = swap;
            }

            p2 = p2->next;
        }
        p1 = p1->next;
    }
}