Increment operator

[Meena Rao]

class counter{
int i=10;
public static void main(String args[]){
counter c1 = new counter();
c1.i=c1.i++;
System.out.println(c1.i);
}}
When I checked o/p is 10. I thought it first assigns the value to the variable and then increments , if this is the case 10 should have been put in i and the same variable should be incremented to show the result as 11.

[Vladimir Kositsky]

Hi!
in this assignment right side is still 10.
if you want get 11 change to
c1.i=++c1.i;
Cheers
[This message has been edited by Vladimir Kositsky (edited December 12, 2000).]

[Meena Rao]

Thanks for the reply.
Yeah, I have tried with ++c1.i. But, what I wanted to know is why the c1.i++ does not increment the value of i and store it in i.

[Rajiv Ranjan]

Hi Meena,
This is because the when you do
c1.i=c1.i++;

The value 10 is first assigned to to i and then after it is incremented, hence the value still remains 10.
whereas if you do ( as per Vladimir )
c1.i=++c1.i;
i is first incremneted and then assigned. Hence the new value is 11

[Sam Wong]

c.i=c.i++;
Breaking this down, what it really does is:
int x = c.i;
c.i = c.i + 1;
c.i = x;
if c.i had a value of 10, it will still have the value 10. Notice that c.i was 11 but got written over by the original value.
Post increment returns the starting value and then increments by 1. Pre increment increments by 1 and then returns the final value.