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# Variables, Type casting ,Concatination and Constants in PhP
- URL: https://scriptcrunch.com/variables-type-casting-concatination-and-constants-in-php/
- Published: 2013-05-04T13:48:00.000Z
- Updated: 2013-05-04T13:48:00.000Z
- Author: Scriptcrunch Editorial
- Tags: #Migrated-1758801465347, #wp, #wp-post, #Import 2025-09-25 11:57

1\. Variables:  
  
***$*** sign is used for defining the variables in PHP. eg: ***$var\_1 =12***. Here the datatype is automatically assigned. You don't have to specify the datatype of a declared variable.  
  
***echo*** is used to output the results.  
  
2\. Changing a variable's data type:  
  
<?php  
  
$a =$b =5.34; //variable declared  
  
echo (($a>4) and ($a>3))."<br/>"; //gives output 1 since it satisfies the condition. && is a conditional operator  
  
settype($a, int); // sets the datatype to int even if the declared variable is of type float  
  
echo "$a"."<br/>"; //displays only 5 since we set the data type to int  
  
echo (int)($b); //displays the int value since $b is typecasted to int .It does not change the real value but it changes the output.  
  
?>

3\. Concatenation :

<?php  
  
$var1 = "ask-cloud,"; //string values has to be put inside the quotes  
  
$var2 = "is a blog for learning";  
  
$num1 = 41; //when declaring numbers you don't need the quotes  
  
$num2 = 42;  
  
echo "$var1" . "$var2" ."<br/>"; //concatenates the two variables var1 and var2 using the dot operator.  
  
echo "$num1" . "$num2" ."<br/>";  
  
?>

4\. Constants:  
  
In PhP you can define constants. The value of the constant remains unchanged throughout the execution of the program. You can define a constant using the ***define ()*** function as shown below. It is common to use capital letters for defining the constants. Also avoid using the php reserved keywords such as boolean, echo etc,,,  
  
<?php  
  
define ("MY_NAME", "michael"); //defines the value for a string  
  
echo MY_NAME . "<br/>";  
  
define ("MY_ID" , 1234); //defines the value for an integer.  
  
echo MY_ID . "<br/>";  
  
?>