4 of 4 added 333 characters in body; added 107 characters in body

C++

#include <cstdlib>
#include <ctime>
#include <iostream>

int deck[52];

void swap(int a, int b) {
    deck[a] ^= deck[b];
    deck[b] ^= deck[a];
    deck[a] ^= deck[b];
}

int r(int a, int b) {
    return a + (rand() % (b - a + 1));
}

void s(int *deck) {
    swap(1, r(2, 51));
    deck[0] *= 100;

    for(deck[0] += 2; (deck[0] % 100) < 51; deck[0]++) {
        swap(deck[0] % 100,
          r(0, 1) ? r(1, (deck[0] % 100) - 1) : r((deck[0] % 100) + 1, 51));
    }
    swap(51, r(1, 50)); 

    deck[0] = (deck[0] - 51) / 100;
    swap(r(1, 51), 0);
}

int main(int a, char** c)
{
    srand(time(0));
    
    for (int i = 0; i < 52; i++)
        deck[i] = i;

    s(deck);
    s(deck);

    for (int i = 0; i < 52; i++)
        std::cout << deck[i] << " ";
}

Avoids swapping elements with themselves, so has to call twice to be random.