Question

How to define a constant in PHP

Answer 1

define("CONSTANT", "php constant");

echo CONSTANT; 


  
/*
run: 
 
php constant
   
*/ 

 

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Answer 2

define("CONSTANT", "php constant");

echo Constant; 


  
/*
run: 
 
Notice: Use of undefined constant Constant - assumed 'Constant' 
   
*/

 

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Answer 3

// define(name, value, case-insensitive)

define("CONSTANT", "php constant", true);

echo CONSTANT . "<br/>"; 
echo Constant; 



  
/*
run: 
 
php constant
php constant
   
*/  

 

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Answer 4

define("PI", 3.14);

echo PI . "\n";

echo constant("PI") . "\n";

echo PI * 2 . "\n";




/*
run:

3.14
3.14
6.28

*/

 

70+ SQL courses for beginners and professionals