How to fix my java error that int cannot be de-referenced

Question

import java.util.*;

public class Hello {
    public static void main(String[] args)    {
       ArrayList<Integer> userInput = new ArrayList<Integer>();
       Scanner scan = new Scanner(System.in);

       System.out.println("Please enter a list of numbers: ");
       while(scan.hasNextInt())
       {
        userInput.add(scan.nextInt());
       }

       for(int userOutput : userInput)
       {
           for(int i = 0; i < userOutput.size(); i++)
           {
               if(i < userOutput.get(i))
               {
                   System.out.println("Largest number is: " + userOutput );
               }
           }
       }
    }
}

In this code userOutput should be an integer. Why the second for loop is required? — Srivignesh, Nov 08 '19 at 06:30
[Java: Finding the highest value in an array](https://stackoverflow.com/questions/1806816/java-finding-the-highest-value-in-an-array) — Abra, Nov 08 '19 at 07:01

score 2 · Accepted Answer · answered Nov 08 '19 at 06:57

You have to use userInput.size() since you want to know the size of the list. If you want to find the largest using a for loop :

       int largest = userInput.get(0);
       for(int i = 1; i < userInput.size(); i++)
       {
           if (largest < userInput.get(i)) 
           {
               largest = userInput.get(i);
           }
       }
       System.out.println("Largest number is: " + largest);

score 0 · Answer 2 · answered Nov 08 '19 at 06:37

0

This is because you are calling size() method in a primitive type data. For your case userOutput is a primitive int type data. So you can't call .size() in it.

answered Nov 08 '19 at 06:37

Alif Hasnain

1,176
1
11
24

score 0 · Answer 3 · answered Nov 08 '19 at 06:56

0

I think you are mistakenly using userOutput inplace of userInput. Here is the corrected code:

       for(int i = 0; i < userInput.size(); i++)
       {
           if(i < userInput.get(i))

Regards, Srikanth Kondaveti

answered Nov 08 '19 at 06:56

Sriko

1
1

score 0 · Answer 4 · answered Nov 08 '19 at 07:00

0

to get the largest number in a collection simply use

Collections.max(userInput);

answered Nov 08 '19 at 07:00

Chikko

81
1
7

How to fix my java error that int cannot be de-referenced

4 Answers4