(Processing) Removing Previously Used Object in Array - arrays

Question

Sorry for the horrible wording of the title. I'm creating a game of "War" in Processing for my Programming class. I need to change my code so that each card that is used is removed from the deck/array. I stumbled upon some posts and Google results mentioning "ArrayList", but I'm still sort of clueless.
The following code displays two separate, random cards and displays two new random cards when the mouse is clicked.
(First Tab 'War')
void draw(){
image(card[imageIndex],40,150);
image(card2[imageIndex2],340,150);
}
void mousePressed(){
imageIndex = int(random(card.length));
imageIndex2 = int(random(card2.length));
}
(Second Tab 'Card')
PImage[] card = new PImage[13];
PImage[] card2 = new PImage[13];
int imageIndex = int(random(0,12)),
imageIndex2 = int(random(0,12));
void setup(){
size(500,500);
card[0] = loadImage("2_of_clubs.jpg");
card[1] = loadImage("3_of_clubs.jpg");
card[2] = loadImage("4_of_clubs.jpg");
card[3] = loadImage("5_of_clubs.jpg");
card[4] = loadImage("6_of_clubs.jpg");
card[5] = loadImage("7_of_clubs.jpg");
card[6] = loadImage("8_of_clubs.jpg");
card[7] = loadImage("9_of_clubs.jpg");
card[8] = loadImage("10_of_clubs.jpg");
card[9] = loadImage("jack_of_clubs.jpg");
card[10] = loadImage("queen_of_clubs.jpg");
card[11] = loadImage("king_of_clubs.jpg");
card[12] = loadImage("ace_of_clubs.jpg");
card2[0] = loadImage("2_of_clubs.jpg");
card2[1] = loadImage("3_of_clubs.jpg");
card2[2] = loadImage("4_of_clubs.jpg");
card2[3] = loadImage("5_of_clubs.jpg");
card2[4] = loadImage("6_of_clubs.jpg");
card2[5] = loadImage("7_of_clubs.jpg");
card2[6] = loadImage("8_of_clubs.jpg");
card2[7] = loadImage("9_of_clubs.jpg");
card2[8] = loadImage("10_of_clubs.jpg");
card2[9] = loadImage("jack_of_clubs.jpg");
card2[10] = loadImage("queen_of_clubs.jpg");
card2[11] = loadImage("king_of_clubs.jpg");
card2[12] = loadImage("ace_of_clubs.jpg");
}

Answer 1

Using ArrayList would look more or less like:
// gonna use strings instead of images
// just to show the idea. I don't have all this images...
ArrayList<String> card = new ArrayList<String>();
ArrayList<String> card2;
int imageIndex, imageIndex2;
String display1, display2;
void setup() {
size(500, 500);
card.add("2_of_clubs.jpg");
card.add("3_of_clubs.jpg");
card.add("4_of_clubs.jpg");
card.add("5_of_clubs.jpg");
card.add("6_of_clubs.jpg");
card.add("7_of_clubs.jpg");
card.add("8_of_clubs.jpg");
card.add("9_of_clubs.jpg");
card.add("10_of_clubs.jpg");
card.add("jack_of_clubs.jpg");
card.add("queen_of_clubs.jpg");
card.add("king_of_clubs.jpg");
card.add("ace_of_clubs.jpg");
card2 = new ArrayList<String>(card);
imageIndex = int(random(card.size()));
imageIndex2 = int(random(card2.size()));
display1 = card.get(imageIndex);
display2 = card2.get(imageIndex2);
card.remove(imageIndex);
card2.remove(imageIndex2);
println("\ncard draw from card : "+ display1);
println("card draw from card2: "+ display2 + "\n");
}
void draw() {
}
void mousePressed() {
if (card.size() > 0) {
imageIndex = int(random(card.size()));
imageIndex2 = int(random(card2.size()));
display1 = card.get(imageIndex);
display2 = card2.get(imageIndex2);
card.remove(imageIndex);
card2.remove(imageIndex2);
println("\ncard draw from card : "+ display1);
println("card draw from card2: "+ display2 + "\n");
} else {
println("The deck is empty...");
}
}

Answer 2

if you have to use arrays then you would have to do something similar to the following code:
PImage[] removeCardFromDeck(PImage deck, int index){
PImage[] newdeck = new PImage[deck.length -1];
int count=0;
for(int i =0 ; i<newdeck.length;i++){
if(count==index) count++;
newdeck[i] = deck[count];
count++;
}
return newdeck;
}
but for this task it is better to use ArrayLists.