Question

While developing a web application in JSF, I came across an expression which was evaluated in a way that I couldn’t follow. Let’s represent the same expression with a simple Java code.

final public class Main
{
    public static void main(String[] args)
    {            
        int x=5;
        int temp=10;

        temp=temp + 1 + x;
        System.out.println("temp = "+temp);

        int var=10;
        var=var++ + x;
        System.out.println("var = "+var);
    }
}

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In the above simple code snippet, the first case is obvious and it displays the value 16 through the statement System.out.println("temp = "+temp);. There is no question at all about it but in the second case, I have represented the same thing using the shorthand operator ++ (var++) and that causes the value 15 to be displayed on the console instead of displaying 16. How is this expression evaluated here?

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Here, there is an obvious thing that should be mentioned. In the expression var++, 10 is first passed and that value (not 11) is used to evaluate the entire expression on the right of the assignment which is in this case var++ + x and then var is incremented by 1. Accordingly, the assignment to itself (var) can not be observed here.
Where was the incrementation lost?

Answer 1

Post increment operator like x++ means first you use the value x then you increment and in our case

 var=var++ + x;

assignment takes precedence.
Try this

 var=++var + x;

and you should get the value of 16.