Can someone explain me why?

Question

var a = 6;
var b = 3;
var z = a++ - --b;
document.write(z);

I will say that the result is 5, but is 4. Why? Does the --b don't count if to it's left is a sign? How can I make it work?

Answer 1

First --b will execute because it's pre decrement, so now b is 2. a will not increment due to its post increment.

So z = 6 - 2 = 4. After this statement only a will increment.

Hope you understand this.

Answer 2

Thank you! Now I understand

Answer 3

yep its 4,

a++ is post increment so a becomes 7 after finishing current statement , but in that line it's 6

but --b is pre decrement, it means decrement happens first then any operation so b becomes 2

so equation becomes
z = 6 - 2

but after this equation
a= 7