#include <iostream>
#include <vector>

void sort(std::vector<int> &arr, int n, int j){
    if(n==1){
        return;
    }

    if(arr[j]<arr[j+1]){
        int tmp = arr[j];
        arr[j] = arr[j+1];
        arr[j+1] = tmp;
    }

    sort(arr, n-1, j+1);
}

int main() {
    std::vector<int> arr = {9,2,7,4};
    int n = arr.size();

    sort(arr, n, 0);

    for(int i=0; i<n; i++){
        std::cout<<arr[i]<<' ';
    }
}