Understanding Conditional Statements in PHP

The PHP code presented in the question revolves around conditional statements, which determine what will be displayed in the browser based on the conditions inside the if, elseif and else blocks.

The correct answer to the question is "Say hello W3docs !!". Let's dissect the code and understand why:

<?php 
   if ( 3 < 3 ) {
       echo "Hello";
   } elseif ( 3 > 3 )  {
       echo "Welcome to ";
   } else {
       echo " Say hello";
   }

   echo "  W3Docs !!";
?>

In the above PHP code, there are three conditions to consider:

1. If 3 is less than 3 — (3 < 3)
2. Otherwise if 3 is greater than 3 — (3 > 3)
3. In all other cases (else)

As we know, both conditions 1 and 2 are false because 3 is not less or greater than 3. So, PHP skips the first two outputs of "Hello" and "Welcome to " and proceeds to the else block where it prints out: " Say hello".

After finishing with the if, elseif, else block, PHP then echoes " W3Docs !!", which gets added directly after the output from the else block, resulting in the final string of "Say hello W3Docs !!".

In a more practical context, these PHP conditional statements can be extremely useful in controlling the flow of your code based on user input, application states, or other conditions. For instance, you can adapt this code to display different welcome messages to different users based on their user status or data.

As a best practice, consider simplifying your conditions as much as possible and avoiding complex condition checks within the same statement. This not only improves code readability but also makes it easier to identify and debug potential issues.

Additionally, if you have independent conditions, always use multiple if statements instead of elseif. The elseif and else statements should be your go-to options only if the subsequent statements are dependent on the preceding ones. This subtle practice can enhance your code performance in PHP.

In conclusion, understanding how conditional statements work in PHP is fundamental to controlling your code's flow. This understanding can be instrumental when creating more complex, dynamic web applications.