array and vector actions

#include <iostream>
#include <array>
#include <vector>
using namespace std;

int main() {
    array<int,5> intarr = {1,2,3,4,5};
    // traverse
    
    for(int a : intarr){
        cout << a*2 << " ";
    }
    for(int& a : intarr){
        cout << a << " ";
    }
    
    for(int& a : intarr){
        cout << a*2 << " ";
    }
    
    // sort
    
    // input from start
    vector<int> arr = {100,200,300};
    arr.insert(arr.begin(),1000);
    cout<<arr[0] << " ";
    // input at last
    arr.insert(arr.end(),2000); // or push_back/emblece_back
    cout<<arr[arr.size()-1] <<" ";
    // input at any instance
    arr.insert(arr.begin()+1,3000);
    cout<<arr[1] <<" ";
    // delete at start
    arr.erase(arr.begin());
    // delete at end
    arr.erase(arr.end());
    // delete at any instance
    arr.erase(arr.begin()+1);
    // search via instance
    intarr[0] = 1;
    return 0;
}