Recursion

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

void helper(int n, vector<int> &v){

    if(n==0)return; //Base case

    //cout<<n<<" "; //Task
    v.push_back(n);
    helper(n-1,v); //Recursive step


}

int main(){

    //to print 5,4,3,2,1

    int n = 5;
    vector<int> v;
    helper(n,v);

    for(int i = 0; i<v.size(); i++){
        cout<<v[i]<<" ";
    }

}