I know how to write a recursive function to print from N to 0: N, N-1, ... 1, 0

But somehow I get stuck on doing the same thing but in increasing order from 0, 1, ... , N.

This is my code for the N to 0:

```
int main() {
    int n = 4;
    backward(n);
    return 0;
}

void backward(int n) {

    if (n == 0) {
        std::cout << n << std::endl;
    }

    else if (n > 0) {
        std::cout << n << " ";
        backward(n - 1);
    }
}

```