Java Operators – What is x After ‘x = x++’?

javaoperatorspost-increment

What happens (behind the curtains) when this is executed?

int x = 7;
x = x++;

That is, when a variable is post incremented and assigned to itself in one statement? I compiled and executed this. x is still 7 even after the entire statement. In my book, it says that x is incremented!

Best Answer

x = x++;

is equivalent to

int tmp = x;
x++;
x = tmp;

Related Solutions

Java Post Increment Operator – Behavior in Return Statement

The key part is that a post increment/decrement happens immediately after the expression is evaluated. Not only does it happen before the return occurs - it happens before any later expressions are evaluated. For instance, suppose you wrote:

class myCounter {
    private int _ix = 1;

    public int ixAdd()
    {
        return _ix++ + giveMeZero();
    }

    public int giveMeZero()
    {
        System.out.println(_ix);
        return 0;
    }
}

That would print out the incremented result as well, because the increment happens before giveMeZero() is called.

Java – Difference Between x++ and ++x in Java

++x is called preincrement while x++ is called postincrement.

int x = 5, y = 5;

System.out.println(++x); // outputs 6
System.out.println(x); // outputs 6

System.out.println(y++); // outputs 5
System.out.println(y); // outputs 6

Best Answer

Related Solutions

Java Post Increment Operator – Behavior in Return Statement

Java – Difference Between x++ and ++x in Java

Related Question