task

#include<iostream>
#include <ctime>

using namespace std;

int main()
{
    setlocale(LC_ALL, "ru");
    srand(time(NULL));

    bool flag = false;
    int a;
    int const SIZE = 10;
    int arr[SIZE];

    for (int i = 0; i < SIZE; i++)
    {
        a = rand() % 20;
        for (int j = 0; j < i; j++)
        {
            if (arr[j] == a)
            {
                i--;
                flag = true;
                break;
            }
        }
        if (flag == false)
        {
            arr[i] = a;
        }
    }
    for (int i = 0; i < SIZE; i++)
    {
        cout << arr[i] << endl;
    }

    return 0;
}