Increment Value Pointer vs Reference

#include <iostream>
using namespace std;

// your code here: define incrementPtr(int* x)
void incrementPtr(int *a) {
    (*a)++;
}
// your code here: define incrementRef(int& x)
void incrementRef(int &a) {
    a++;
}
int main() {
    int n;
    cin >> n;

    int a = n;
    incrementPtr(&a);
    cout << "After incrementPtr: " << a << "\n";

    int b = n;
    incrementRef(&b);
    cout << "After incrementRef: " << b;

    return 0;
}