（如果）语句在从另一个php文件中包含它时不起作用

Question

I have two php files first is sample.php and the second is if.php. I have some code written in sample.php basically declaration of two variables and an else statement. I have the if statement in if.php file which I'm including before else statement. But on running my code its shows an error:

Unexpected 'else'...etc.

Can you please help me figuring out what is wrong with the code?

Sample.php

<?php
$a=10;
$b=20;

include 'if.php';
else
{
echo $b.' is greater';
}
?>

if.php

<?php
if($a>$b)
{
echo $a.' is greater';
}
?>

Answer 1

include 'if.php';
else

Nice, there is no such thing as include else. Even if you have an if clause at the end of your included file, the include line breaks its sequence.

else can only come after either an if or an else if block, no third option. Period.

Here is how PHP parser will see your 2 files

if($a>$b){
  echo $a.' is greater';
}
include "if.php";
else {
  echo 'na';
}

Which is clearly invalid.

If you still want to keep things as they are, like you mentioned in the comments. You can do 1 small trick (amongst many other methods). Make your else another if which is contrary to the first if. Like

if.php

if($a>$b){
  echo $a.' is greater';
}

main file

include "if.php";
if($a<=$b) {
  echo 'na';
}