java increment operation not incrementing

Question

public static void main(String[] args) {
    int x = 10;
    x = x++;
    x = x++;
    x = x++;
    System.out.println(x);
}

Why is the output 10 when the expected output is 13?

Answer 1

Post increment operator x++ returns the original value of x. Therefore x=x++ assigns the old value of x back to x.

Answer 2

This is probably what you weant to do

public static void main(String[] args) {
    int x = 10;
    x++;
    x++;
    x++;
    System.out.println(x);
}