哪个if语句更有效？ [关闭]

Question

Which if statement below is more efficient in PHP:

$A=@"llaweikj";
$B=@"aesrwh";
$C=@"uymy";
$D=@"xcvb";

if ( ($A==$B) && ($C==$D) ) {
    //Do something with it
}

OR

if ($A==$B) {
    if ($C==$D) {
       //Do something with it
    }
}

What would be more efficient?

Answer 1

In your question, Both statements are different.

In first statement:

if ( ($A==$B) && ($C==$D) )

First it will check if A is equals to B and C is equals to D then the code will execute within the if statement. Means both condition needs to be true.

But in your second statement:

if ($A==$B) 
if ($C==$D)

the code inside the true condition will execute if A is equals to B then first if condition will execute and if if C is equals to D then second statement will execute. In case of both are true then both if condition will execute.

EDITED:

After updating your question, the answer is here:

Your first condition if ( ($A==$B) && ($C==$D) ) is more efficient. In second statement there is unnecessary if, even though you can check both condition with in single if condition. so your first condition will execute fast.