Why are there different outputs when I change the order in the Code of different ways of incrementing by 1 ?

Question

example 1

int x=0;
System.out.println(x);
x=x++;
System.out.println(x);
x=x+1;
System.out.println(x);
×+=1;
System.out.println(x);

// prints 0,0,1,2

example 2

int x=0;
System.out.println(x);
x=x+1;
System.out.println(x);
x+=1;
System.out.println(x);
×++;
System.out.println(x);

// prints 0,1,2,3

Depending on wether x++ is the first operation (example1) or the last Operation (example 2) it will increment x ?

edit: line 3 I messed up. didn't mean x=x++ but only x++. Then the output is the same in both.

Answer 1

Because "x++" means "add 1 after current operation" while "++x" increments before operation.
x = 1; // x is 1
x = x++; // x is still 1
cout << x; // x is 2
You need a valid operation to make x++ work or make it as ending operation.