Help Understanding a piece of Code

[goatslayer]

There is this neat piece of code on the next for converting a decimal value into hex, I can't quite figure out how it works, I was wondering if anyone could help.

#include <iostream>
using namespace std;

int main() {
    int n;
    while (cin >> n) {
        cout << "decimal: " << n << endl;
      

         cout << "size of int: " << sizeof(int) << endl;

        //--- Print hex with leading zeros
        cout << "hex    : ";
        for (int i=2*sizeof(int) - 1; i>=0; i--) {
            cout << "0123456789ABCDEF"[((n >> i*4) & 0xF)];
        }
        cout << endl << endl;
    }
return 0;
}

My bitwise is a little flaky to say the least, but I'm eager to learn it. I was hoping some light shed on this might help me.

The original source is Convert to Hex