How to copy an array to another array in C++

#include <bits/stdc++.h>
using namespace std;
int a[100000], b[10000];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
    }
    cout << "Before Copy\n";
    for (int i = 0; i < n; i++)
    {
        cout << a[i] << " ";
    }
    cout << "\n";
    for (int i = 0; i < n; i++)
    {
        cout << b[i] << " ";
    }
    cout << "\n";

    for (int i = 0; i < n; i++)
    {
        b[i] = a[i];
    }
    cout << "After copy\n";
    for (int i = 0; i < n; i++)
    {
        cout << a[i] << " ";
    }
    cout << "\n";
    for (int i = 0; i < n; i++)
    {
        cout << b[i] << " ";
    }
}