Adding to ArrayList

Question

I can't figure out why I can't add items to the ArrayList. I have tried a couple different ways of adding items and they don't work.

class Problem {
public ArrayList<String> problems = new ArrayList<String>();
public ArrayList<String> answers = new ArrayList<String>();
private String question1 = "What is 2+2?";
private String question2 = "What is the square root of 25";
private String question3 = "What is the next number in the sequence? {2, 4, 6}";
private String question4 = "What is 8*8?";
String[] temp1 = {question1, question2, question3, question4};
for (String s : temp1)
 problems.add(s);
}

I have also tried

problems.add(question1);
problems.add(question2);
problems.add(question3);
problems.add(question4);

This does not work either.

Compiler says that identifier is expected.

• Dave Newton: Adding the items needs to be in a method or in an initializer. Why do you put them in an array then add to the list? Why not just add them to the list?

Answer 1

Try adding import java.util.ArrayList; to the top of your file.

You also need a main method to run, with a signature like this:

public static void main(String[] args)

Also, you should make the string constants final (and/or static) if you don't plan on changing them.

Finally, temp1 is the default ("friend") visibility.

I'm assuming this is a code snippet rather than what you actually ran.

• bilestrojanman: Yes its just a small piece of a larger program. Adding the main() method seems to have solved my problem. Thank you. Dumb mistake :P

Answer 2

import java.util.ArrayList;
class Problem {
public static ArrayList<String> problems = new ArrayList<String>();
public static ArrayList<String> answers = new ArrayList<String>();
private static String question1 = "What is 2+2?";
private static String question2 = "What is the square root of 25";
private static String question3 = "What is the next number in the sequence? {2, 4, 6}"; 
private static String question4 = "What is 8*8?";
public static void main(String [] args) {
String[] temp1 = {question1, question2, question3, question4};
for (String s : temp1)
 problems.add(s);
System.out.println(""+problems);
}

}

Answer 3

Actually, you're missing a method declaration.

Try putting your code inside of a Main method:

public static void main(String[] args) {
 String[] temp1 = {question1, question2, question3, question4};
 for (String s : temp1)
 problems.add(s);
 }
}