I am a complete beginner with Java and am having trouble understanding how to pass objects around between classes and methods. I have made some progress, however my app now fails when I try to create playing cards inside a for loop. It works fine if I remove the loop. Here is the first part of the class that contains the error:
public class Testing
{
public static void main(String[] args)
{
int Deal = 1;
for(int Hand = 0; Hand < Deal; ++Hand)
{
//instantiate and derive values for Player
Card card1 = new Card();
card1.setSuit(); //assign card 1's suit
card1.setValue(); //asign card 1's value
//instantiate and derive values for Computer
Card card2 = new Card();
card2.setSuit(); //assign card 2's suit
card2.setValue(); //assign card 2's suit
//compare the two cards and make sure they are different
cardCompare(card1,card2);
}
//output the two cards to the screen
output(card1,card2);
}
This is the error I get:
Testing.java:26: error: cannot find symbol
output(card1,card2);
^
symbol: variable card1
location: class Testing
Testing.java:26: error: cannot find symbol
output(card1,card2);
^
symbol: variable card2
location: class Testing
2 errors
Since the code works if I remove the for loop, I'm assuming that somehow the names card1 and card2 are not visible outside the loop? If I wanted to create ten or twenty cards, I'd want to do that in a loop, so I must be missing something about instantiating new objects and using them elsewhere in the program.
Thanks for your help.
**Update: thanks for the initial feedback. I see now that if I move my instantiate statements outside the for loop, I could theoretically assign new values for those objects over and over again using a loop, which is all I need to complete this particular task.
I'm still curious though, is it not possible to instantiate new objects inside a loop, but still use them outside the loop? It seems like this must be possible somehow.
public class Testing
{
public static void main(String[] args)
{
int Deal = 1;
//instantiate and derive values for Player
Card card1 = new Card();
//instantiate and derive values for Computer
Card card2 = new Card();
for(int Hand = 0; Hand < Deal; ++Hand)
{
card1.setSuit(); //assign card 1's suit
card1.setValue(); //asign card 1's value
card2.setSuit(); //assign card 2's suit
card2.setValue(); //assign card 2's value
//compare the two cards and make sure they are different
cardCompare(card1,card2);
}
//output the two cards to the screen
output(card1,card2);
}
The card1 and card variables are declared inside the for loop and is thus only visible inside of the loop. To use it outside of the loop, you must declare it before the loop. Please read up on Java scoping rules.
Both card1 and card2 are in scope of the for loop, not the rest of main(). Move your initialization to before the for.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With