Number Of Ways Of Coin Change By Recursion

#include<bits/stdc++.h>
using namespace std;

int ways(int coin[], int n, int tk)
{
    if(tk == 0)
        return 1;

    if(tk < 0)
        return 0;

    if(n <= 0 && tk >= 1)
        return 0;

    return ways(coin, n-1, tk) + ways(coin, n, tk - coin[n-1]);
}

int main()
{
    int n, i, tk;
    cout << "Enter Coin Number :: ";
    cin >> n;

    int coin[n];

    cout << "Enter Each Coin Value :: ";
    for(i=0;i<n;i++)
        cin >> coin[i];

    cout << "Enter Total Amount :: ";
    cin >> tk;

   cout << "\nNumber Of Ways Of Coin Change :: " << ways(coin, n, tk) << "\n";

    return 0;
}