Zend Preparation | PHP Quiz (Learning Mode)

PHP Basics Learning Mode

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Consider the following PHP script:

<?php
function b($a = 4)
{
  $a = $a / 2;
  return $a;
}
$a = 10;
b($a);
echo $a;
?>

What will be the output?

The script will throw an error message.

Explanation: In the given script, the output will be 10 since the value of variable $a will not be affected by the value of $a inside the function b() (due to function scope). Variable scope describes where in a program's text the variable may be used, while the extent (or lifetime) describes when in a program's execution a variable has a value. PHP has three types of variable scopes:

Function Scope: Variable scope exists within the function where the variable was defined.
Global Scope: Variable scope exists everywhere in the PHP script.
Class Scope: Variable scope exists within a class where the variable was defined.
Answer option A is incorrect. This answer will be displayed when you print the result of the function b(). For this, you will have to execute the following PHP code:

<?php
function b($a = 4)
{
 $a = $a / 2;
 return $a;
}
$a = 10;
b($a);
echo b($a); 
?>

Answer option C is incorrect. This answer would be displayed when you will not pass any argument to the function b(). In this situation, the default argument $a=4 will be passed to the function b(). So, for getting the output 2, you will have to run the following script:

<?php
function b($a = 4)
{
 $a = $a / 2;
 return $a;
}
$a = 10;
b($a);
echo b();
?>

Reference: http://php.net/manual/en/language.variables.scope.php