method return style

[Udayan Kumar]

Hi All,

Sorry if this question sounds naive.
Recently I saw a piece of code something like this
-----------------------------------------
/**
* Test if the current position is a valid position in the list.
* @return true if the current position is valid.
*/
public boolean isValid( ) {
return current != null;
}
ListNode current;
------------------------------------------
the statement (return current != null) is something I did not get convincingly. How does this statement evaluate & work.


-Uday

[John Dell'Oso]

If the condition (current != null) is true, then the method returns true, otherwise it returns false.

Regards,
JD

[Bob Ruth]

Just a way to "peel it apart"....

look at the method declaration.... it says that the method returns boolean.

That means that, when the method exits it needs to return a boolean value, either true or false.

Now if you look at everything after the return, it is an expression that makes a comparison that is either going to be true or false, based on the specified test.

[Manuel Leiria]

Originally posted by Udayan Kumar:
Hi All,

Sorry if this question sounds naive.
Recently I saw a piece of code something like this
-----------------------------------------
/**
* Test if the current position is a valid position in the list.
* @return true if the current position is valid.
*/
public boolean isValid( ) {
return current != null;
}
ListNode current;
------------------------------------------
the statement (return current != null) is something I did not get convincingly. How does this statement evaluate & work.


-Uday

It's the same as:

/**
     * Test if the current position is a valid position in the list.
     * @return true if the current position is valid.
     */
    
    public boolean isValid( ) {
        boolean result = false;
        if(current != null)
          result = true;
        else
          result = false;
        return result;
    }
 ListNode current; 

[Stan James]

It's also the same as

boolean result = current != null;
return result;

With so many ways to say the same thing, it's no surprise that it can be confusing. Do you see the common bit in every one of these that the tiny expression "current != null" can be replaced by true or false just about anywhere it is used? And that means you can use an expression just about any place you need true or false.