I'm fairly new to Java and I'm using BlueJ. I keep getting this "Int cannot be dereferenced" error when trying to compile and I'm not sure what the problem is. The error is specifically happening in my if statement at the bottom, where it says "equals" is an error and "int cannot be dereferenced." Hope to get some assistance as I have no idea what to do. Thank you in advance!

public class Catalog { private Item[] list; private int size; // Construct an empty catalog with the specified capacity. public Catalog(int max) { list = new Item[max]; size = 0; } // Insert a new item into the catalog. // Throw a CatalogFull exception if the catalog is full. public void insert(Item obj) throws CatalogFull { if (list.length == size) { throw new CatalogFull(); } list[size] = obj; ++size; } // Search the catalog for the item whose item number // is the parameter id. Return the matching object // if the search succeeds. Throw an ItemNotFound // exception if the search fails. public Item find(int id) throws ItemNotFound { for (int pos = 0; pos < size; ++pos){ if (id.equals(list[pos].getItemNumber())){ //Getting error on "equals" return list[pos]; } else { throw new ItemNotFound(); } } }
}

1

7 Answers

id is of primitive type int and not an Object. You cannot call methods on a primitive as you are doing here :

id.equals

Try replacing this:

 if (id.equals(list[pos].getItemNumber())){ //Getting error on "equals"

with

 if (id == list[pos].getItemNumber()){ //Getting error on "equals"

2

Basically, you're trying to use int as if it was an Object, which it isn't (well...it's complicated)

id.equals(list[pos].getItemNumber())

Should be...

id == list[pos].getItemNumber()

4

Assuming getItemNumber() returns an int, replace

if (id.equals(list[pos].getItemNumber()))

with

if (id == list[pos].getItemNumber())

Change

id.equals(list[pos].getItemNumber())

to

id == list[pos].getItemNumber()

For more details, you should learn the difference between the primitive types like int, char, and double and reference types.

As your methods an int datatype, you should use "==" instead of equals()

try replacing this if (id.equals(list[pos].getItemNumber()))

with

if (id.equals==list[pos].getItemNumber())

it will fix the error .

Dereferencing is the process of accessing the value referred to by a reference . Since, int is already a value (not a reference), it can not be dereferenced. so u need to replace your code (.) to(==).

try

id == list[pos].getItemNumber()

instead of

id.equals(list[pos].getItemNumber()

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