PHP If, Else, ElseIf

Operator if - is one of the most important operators in PHP.

The syntax of the conditional operator:

if (condition)
   operator;

Condition - a logical expression that can be true (TRUE) or false (FALSE).

The operator - is executed when the condition is true and is not executed when the condition is false!

<?php 

   if(2 > 0)
       echo ( "Hello Web !!!");

?>

In this example operator echo ( "Hello W3docs !!!"); was executed, because 2 > 0 is true!

If we want to use several operators, we need to enclose them in braces {and }:

<?php 

   if(2 > 0)
   {
        echo ( "Hello ");
        echo ( "Web !!! ");
 	echo ( "!!!");
   }

?>

Operator if .. else - is used when we need to execute code if a condition is true and another code if the condition is false.

The syntax :

if (condition)
   operator1;
else
   operator2;

If the condition is true, then executed operator1, if false then operator2.

If operator1 or operator2 should consist of several teams, then they are enclosed in braces.

<?php 

   if(2 > 0)
   {
        echo ( "true");        
   }
   else
   {
        echo ( "false");        
   }

?>

In this example, the echo ( "true"); operator will be executed, because condition (2 > 0) is true!

Operator if .. elseif .. else - is used, when we need to check another condition when the first condition is false.

The syntax :

if (condition)
   operator1;
elseif (contition2)
   operator2;
else
   operator3;

If condition1 is true, executed operator1, if false, then checked condition2, if condition2 is true, executed operator2, if false then executed operator3.

<?php 

   if(2 < 0)
   {
        echo ( "2 < 0 is true");        
   }
   elseif(2 > 0)
   {
        echo ( "2 > 0 is true");        
   }
   else
   {
        echo ( "conditions are false");        
   }

?>

In this example, operator echo ( "2 > 0 is true"); will be executed, because condition (2 > 0) in elseif is true !