enhanced usage of question mark in java

Question

last = cur = cur == null ? head : cur.link;

I am trying to understand this using if and else statement. But I am stuck on this one. Can anyone help this out

Answer 1

Your expression is equal to

if (cur == null) {
    cur = head;
} else {
    cur = cur.link;
}
last = cur;

You can split the example into two parts for easier understanding. Part 1:

last = cur = xxx;

is the same as

cur = xxx;
last = cur;

Part 2:

cur = cur == null ? head : cur.link;

is the same as

if (cur == null) {
    cur = head;
} else {
    cur = cur.link;
}

And part 2 would be even easier to understand if cur didn't appear three times. So this is simpler:

a = b == null ? c : d;

is the same as

if (b == null) {
    a = c;
} else {
    a = d;
}