Question

** Dup: What's the difference between X = X++; vs X++;? **

So, even though I know you would never actually do this in code, I’m still curious:

public static void main(String[] args) {     int index = 0;     System.out.println(index);   // 0     index++;     System.out.println(index);   // 1     index = index++;     System.out.println(index);   // 1     System.out.println(index++); // 1     System.out.println(index);   // 2 } 

Note that the 3rd sysout is still 1. In my mind the line index = index++; means ‘set index to index, then increment index by 1’ in the same way System.out.println(index++); means ‘pass index to the println method then increment index by 1’.

This is not the case however. Can anyone explain what’s going on?

Answer 1

this is a duplicate question.

EDIT: I can’t seem to find the original 😛 oh well

a = a++ uses the postincrement, which your compiler interprets as:

a = function() {    var old_value = a;    a++;    return old_value; } 

EDIT 2: What's the difference between X = X++; vs X++;?