cannot find symbol for method in a class of array objects - object

Question

I have a class Card to represent a deck of cards as an array of objects Card[], with methods to shuffle and print the deck. I have a test class TestCard to generate the deck (in TestCard) then shuffle and print the deck (as methods in Card.) I get the message
TestCard.java:17: error: cannot find symbol
mydeck.writeDeck();
^
symbol: method writeDeck()
location: variable mydeck of type Card[]
Here is the Card.java code.
public class Card {
public static final int NUMCARDS=52;
String suit;
int value;
String name;
public Card() {
suit = " ";
value = 0;
name = " ";
}
public Card(String suit, int value, String name) {
this.suit=suit;
this.value=value;
this.name=name;
}
public void setData(String su,int va, String na) {
suit = su; value = va; name = na;
}
public void writeDeck(Card[] cards) {
int count=0;
for (Card mycard : cards ) {
System.out.print(mycard.name+mycard.suit);
count++;
if (count==13) {
System.out.println();
count= 0;
}
}
System.out.println();
}
private void swap(Card[] arr,int i, int j) {
Card temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
public void shuffle(Card[] carr) {
int index;
for (int i=NUMCARDS-1; i>0; i--) {
index = (int) (Math.random() * (i+1));
swap(carr, i, index);
}
}
}
and here is TestCode.java code
public class TestCard {
public static final int NUMCARDS=52;
public static void main(String args[]) {
Card[] mydeck = new Card[NUMCARDS];
for (int i=0; i<NUMCARDS; i++) {
int j=i%13+1;
String v;
v = Integer.toString(j);
String s;
if (i<13) s="C";
else if (i<26) s="D";
else if (i<39) s="H";
else s="S";
mydeck[i] = new Card(s,j,v);
}
System.out.print(mydeck[5].suit+mydeck[5].value);
mydeck.writeDeck();
mydeck.shuffle();
mydeck.writeDeck();
}
}
I have spent 8 hours trying various fixes, using tutorials from various we sites, but have not succeeded.

Answer 1

mydeck.writeDeck(); is trying to call the writeDeck() method of the instance mydeck. But if you look at the code:
Card[] mydeck = new Card[NUMCARDS];
my deck is not a Card object, it's an array of Card objects. According to your code, you must pass in a Card[] as a parameter.
Turn .writeDeck(Card[] cards) into a static method:
public static void writeDeck(Card[] cards)
and then invoke the method like so:
Card.writeDeck(mydeck)

Answer 2

Marvin's answer worked like a charm. According to the Oracle documentation, for a method to work on an array of objects, the method must be defined for the object. But you can't just simply say arrayvar.method(). You have to say Objectclass.method(arrayvar). Good news is you can pass two array variables if you are working with both.