Question

I can’t figure this out. I need to do and if else.

If A is not empty then it must equal B & C must = D & E must = F

It is the A & B part I think that has me messed up. I cant get it to work only if A is not empty

 if( ( !empty($data[0]) && trim($data[0]) == $_POST['firstname'] ) || trim($data[1]) == $_POST['lastname'] && $_POST['password'] == $password)

It is that A is optional that gets me.

Answer 1

Why do it all in one go?

If (A is not empty) then 
    if A == B && C == D && E == F then

Which I think comes out as:

if ( !empty($data[0]) {
   if ((trim($data[0]) == $_POST['firstname'] ) && trim($data[1]) == $_POST['lastname'] && $_POST['password'] == $password) {