Print digits using recursion

#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define ll long long
#define ull unsigned long long
#define MOD 1000000007
#define PI 3.14159265
#define ceil(a, b) ((a / b) + (a % b ? 1 : 0))
#define nl '\n'
void Start_Crushing(){
    ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
    freopen("error.txt", "w", stderr);
#endif
}
void printing(int n){
    if(n <= 0) return;

    printing(n / 10);
    cout << n % 10 << ' ';

}
void solve(){
    int n; cin >> n;
    if(n == 0){
        cout << 0;
        return;
    }
    printing(n);
}
int main(){
    Start_Crushing();

    int t = 1;
    /*is Single Test case?*/ cin >> t;
    while (t--) {
        solve();
        cout << "\n";
    }

    cerr << "time taken : " << (float)clock() / CLOCKS_PER_SEC << " secs" << endl;

    return 0;
}