Card game rule: the hand is drawn from a pack of cards (no jokers). Play cards ONLY when they are

Help me how to take the input. I can not understand what to add in the main method

Card game rule: the hand is drawn from a pack of cards (no jokers). Play cards ONLY when they are 3 of a kind (...AAA... ) or 4 of a kind(...AAAA...). a straight flush of 3 or more cards(...JQK... or ...A23456…... in the same suit). Find out whether the player will be able to play the whole hand

//input a 4X13 matrix with 4 suits and 13 ranks of cards. set cards[suit][rank] to 1 if this card in hand.
public static boolean handClear(int[][] cards, int hand) {
if(hand == 0) return true;
for(int rank = 12; rank >= 0; rank--) {
for(int suit = 0; suit < 4; suit++) {
if(cards[suit][rank] == 1) { //if cards[suit][rank] in hand
cards[suit][rank] = 0; hand--;
int smallerRank = rank == 0 ? 12: rank - 1; // look for straight flush that end with this card
// watch for Ace as a special case that ***QKA and A23*** both valid
if(cards[suit][smallerRank] == 1) {
cards[suit][smallerRank] = 0; hand--;
int r = smallerRank - 1;
for(; r >= 0 && cards[suit][r] == 1; r--) {   //try playing the straight flush found
cards[suit][r] = 0; hand--;
if(handClear(cards, hand)) return true;
}
r++;
for(; r <= smallerRank; r++) {  //backtrack if play did not work
cards[suit][r] = 1; hand++;
}
}
//look for 3/4 of a kind for cards[suit][rand]
int n = cards[0][rank] + cards[1][rank] + cards[2][rank] + cards[3][rank];
if(n == 3 || n == 2) {
int tmp1 = cards[(suit + 1) % 4][rank],
tmp2 = cards[(suit + 2) % 4][rank],
tmp3 = cards[(suit + 3) % 4][rank];
cards[(suit + 1) % 4][rank] = 0; //try playing the 3/4 of a kind
cards[(suit + 2) % 4][rank] = 0;
cards[(suit + 3) % 4][rank] = 0;
hand -= n;
if(handClear(cards, hand)) return true;
cards[(suit + 1) % 4][rank] = tmp1;   //backtrack if play did not work
cards[(suit + 2) % 4][rank] = tmp2;
cards[(suit + 3) % 4][rank] = tmp3;
hand += n;
}
cards[suit][rank] = 1; hand++;
}
}
}
return false;
}

I believe you just want an explanation of how to initially call the method, that you posted in your question.

The method parameter cards represents all the cards in a deck.
There are four suits, i.e. Clubs, Diamonds, Hearts and Spades.
Obviously each suit has an associated index. As I understand the code you posted, it is OK to simply associate an index with a suit, arbitrarily. So let's assume the following:

0 = Clubs
1 = Diamonds
2 = Hearts
3 = Spades

Hence the dimensions of the array cards should be 4 and 13, since there are thirteen cards in each suit. So you need to create a two-dimensional array, e.g.

int[][] cards = new int[4][13];

Now you need to associate a card in a suit with an index. Let's assume that the Ace has index 0 (zero) and that the King has index 12 (twelve).

This means that cards[0][0] represents the Ace of Clubs and cards[2][10] represents the Jack of Hearts.

My Poker knowledge is a bit rusty, so I may be wrong, but a Poker hand consists of five cards.

So you need to initialize cards and set each element to 0 (zero), i.e.

for (int i = 0; i < 4; i++) {
    for (int j = 0; j < 13; j++) {
        cards[i][j] = 0;
    }
}

Now you need to "deal" a hand. You need to set the value in cards to 1 (one) for the index of the card. How you deal the cards randomly, I don't know but let's say you dealt yourself a 7 of Spades, that would mean you need to do the following.

cards[3][6] = 1;

Note that the method you posted, i.e. handClear, is a recursive method. That means the method calls itself. All recursive methods must have a condition that terminates the recursion. In method handClear that condition is when the [method] parameter hand equals 0 (zero). That means that the value of hand must be the number of cards in the hand that was "dealt". As I said earlier, for Poker, I believe it is five. But it doesn't matter since the method handClear will handle any value of parameter hand that it receives.

So in order to initially call method handClear, you need to determine how many cards make up a hand, for example 5 for Poker. Then you have to create the two-dimensional array and initialize it as I explained above, and finally you have to select hand different elements in cards and set the element value to 1 (one). Then you can call method handClear.

A very simple example of the above:

int[][] cards = new int[4][13];
for (int i = 0; i < 4; i++) {
    for (int j = 0; j < 13; j++) {
        cards[i][j] = 0;
    }
}
int hand = 5;
cards[0][0] = 1; // Ace of Clubs
cards[1][0] = 1; // Ace of Diamonds
cards[2][0] = 1; // Ace of Hearts
cards[3][0] = 1; // Ace of Spades
cards[0][1] = 1; // Two of Clubs
if (handClear(cards, hand)) {
    System.out.println("You have a winning hand!");
}