Question

Write a function that takes a list of integers as input and returns a list with only the even numbers in descending order (Largest to smallest)

Example: Input list: [1,6,3,8,2,5] List returned: [8, 6, 2]

Do not use any special or built in functions like append, reverse etc.

Answer 1

#include <bits/stdc++.h>
using namespace std;
void bubbleSort(vector<int> &arr){
    int n = arr.size();

    for(int i=0;i<n;i++){ // loop for the bubble sort
        for(int j=0;j<n-i-1;j++){
            if(arr[j]<arr[j+1]){
                int temp = arr[j];
                arr[j] = arr[j+1];
                arr[j+1] = temp;
            }
        }
    }
    return;
}
vector<int> solve(int n, vector<int> &v){
    vector<int> res; // forming the result list which is going to be returned

    for(int i=0;i<n;i++){ // iterating on all the elements of given list of elements
        if(v[i]%2 ==0){ // checking the condition for even elements
            res.push_back(v[i]);
        }
    }

    bubbleSort(res); // calling the bubble sort function to sort in descending order

    return res; // returning the list of even elements arranged in descending order
}
int main() {
    int n; // n is the variable 
    cin>>n; // taking input -  no of elements present in the list

    vector<int> v(n); // forming the list of n elements
    for(int i=0;i<n;i++) cin>>v[i]; // taking input - the elements present in the list

    vector<int> res = solve(n,v); // calling the required function solve - to seperate the even elements
    

    for(int i=0;i<res.size();i++) cout<<res[i]<<" "; // printing the resulted list 
    cout<<endl;




}