How to working of : x = x++?

Question

Java Code below :

    int x = 10;
    while (x != 15){
       x = x++;
       System.out.println("Value X " + x);
    }

execute : endless Loop ? why ?

See: http://stackoverflow.com/questions/7911776/what-is-x-after-x-x — Quetzalcoatl, Apr 08 '13 at 09:54

score 2 · Answer 1 · answered Apr 08 '13 at 09:55

2

Because x will never change and always will be 10. Read JLS.

answered Apr 08 '13 at 09:55

Andremoniy

score 2 · Answer 2 · edited May 23 '17 at 12:29

2

I may be wrong but x++ incrementes x after reading it so x = x++ means x = x. You should use x = ++x instead.

edited May 23 '17 at 12:29

Community

answered Apr 08 '13 at 09:55

StepTNT

score 2 · Answer 3 · answered Apr 08 '13 at 09:55

2

Becouse you assign the old value of x to x befor you increase the value! Try this:

int x = 10;
while (x != 15){
   x++;
}

or

int x = 10;
while (x != 15){
   x = ++x;
}

answered Apr 08 '13 at 09:55

nano_nano

score 1 · Answer 4 · answered Apr 08 '13 at 09:54

1

x++; increments the value of x then returns the old value of x.

THEN x = (that number) executes, meaning the mutation x++ did of x is undone.

answered Apr 08 '13 at 09:54

Patashu

score 1 · Answer 5 · edited Apr 08 '13 at 10:19

1

The line x = x++; should be x++;

edited Apr 08 '13 at 10:19

mata

answered Apr 08 '13 at 09:57

subodh

score 0 · Answer 6 · answered Apr 08 '13 at 09:54

0

Because x = x++ will assign the result of the operation x++ to x. What you want is only x++;, which increments the value of x by one.

answered Apr 08 '13 at 09:54

David Hedlund

6 Answers6