dose increment operator works differently at different places?

[Rauhl Roy]

 class PrePostDemo {
    public static void main(String[] args){
         int i = 3;
	  i++;
	  System.out.println(i);	// "4"
	  ++i;			   
	  System.out.println(i);	// "5"
	  System.out.println(++i);	// "6"
	  System.out.println(i++);	// "6"
	  System.out.println(i);	// "7"
    }
}

May i know why Line number 5 and 7 are giving incremented result but not line number 8 and 9.

why the result of increment (@ 8 and 9 lines) is not being directly reflecting on the output.

[Ove Lindström]

It is the way Java reads your code.

Line 4: the variable i, increase it
Line 5: print variable i.
Line 6, increase variable i.
Line 7: print variable i.
Line 8: with i, increase it then print it
Line 9: print variable i, then increase it.

[Jesper de Jong]

The postfix increment operator, where the ++ is after the variable name, will return the old value of the variable. So if i = 5, and you print the value of i++, you will get 5 (and i is incremented to the value 6).

The prefix increment operator, where the ++ is before the variable name, will return the new value of the variable. So if i = 5, and you print the value of ++i, you will get 6 (and i is incremented to the value 6).

[fred rosenberger]

This is why after running this code:

int i = 3;
i = i++

i will still be 3. the i++ says 'return the old value, but increase it by 1. So we set i to 4 (due to the ++), we return the old value of 3, and then assign 3 to i.

Therefore, never never never write line 2.

[Campbell Ritchie]

There is no such thing as "the increment operator". There are two increment operators.