Wednesday, December 2, 2015

Language: php (1).........

php: PHP Hypertext preprocessor
Its a server-side scripting language (data collect, save, add, delete, modify, encrypt). It is much like HTML (HTML-embedded) and syntax is C-like. Its case-sensitive
Web development and database (MYSQL, Oracle, Microsoft SQL Server) can interact through php
First released in 1996
It supports protocols as IMAP, POP3, LDAP
Characteristics of php: simple, flexible, forgiving, secure, efficient, fast, compatible
Componnets needed for php web page operation: web server, database, php parser
Script extension is .php
php configuation file is php.ini
php tag style  <?php...?>
Comments: # for single line
                   /* for multi-line*/
Executing script from command prompt:  php script.php
php constants: _LINE_, _FILE_,_FUNCTION_,_CLASS_,_METHOD_
-------------------------
#Hello script 
<html>
   <head>
      <title>Online PHP Script Execution</title>    
   </head>
 
   <body>
   
      <?php
         echo "<h1>Hello</h1>";
      ?>
 
   </body>
</html>
Hello
-------------------------
#Case sensitive nature of php
 <html>
   <body>
   
      <?php
         $age = 21;
         print("I am $age<br>");
         print("I am $Age<br>");
      ?>
   
   </body>
</html>
I am 21
I am 
-------------------------
#If statement, condition check, braces to make blocks
<html>
   <head>
      <title>Online PHP Script Execution</title>  
   </head>

   <body>
   
      <?php
         if (4 == 2 + 2)
   print("TRUE<br>");
   
        if (5 == 2 + 2){
   print("FALSE");
   };
      ?>

   </body>
</html>
TRUE
-------------------------
Variables (Integers, double, boolean)
Integers
<?php
   $a = 7;
   $b = 3;
   $sum = $a + $b;
   $minus = $a - $b;
   print ("$a + $b = $sum <br>");
   print ("$a - $b = $minus <br>");
?>
7 + 3 = 10
7 - 3 = 4 
-----------
Doubles
<?php
   $a = 2.7;
   $b = 5.8;
   $total = $a + $b;
   print ("$a + $b = $total <br>");
?>
2.7 + 5.8 = 8.5 
-----------
Boolean
<?php
   if (TRUE)
   print("Yes<br>");

else
   print("No <br>");
?>
True
-----------
Assigning multiple lines to single variable
<?php
$abc =<<<_XML_
<abc>
<description>Winter night.</description>
<description>Its raining.</description>
</abc>
_XML_;
echo <<<END
Mid December.
END;
print $abc;
?>
Mid December. Winter night. Its raining.
-----------
<?php
   define("MINSIZE", 24);
   
   #echo MINSIZE;
   echo constant("MINSIZE"); 
?>
24
-----------
If......else
<?php
   $d=date("D");
         
    if ($d=="Sun")
         echo "Play"; 
         
    else
        echo "Study"; 
?>
Study
-----------
elseif (When at least one condition is true)
<?php
       $d=date("D");
         
       if ($d=="Sat")
            echo "Hike";
         
       elseif ($d=="Sun")
            echo "Play"; 
         
       else
            echo "Study"; 
      ?>
Study
-----------
switch (evaluates, matches, if found executed, otherwise executes a specified default code)
 <?php
         $d=date("D");
         
         switch ($d)
         {
            case "Mon":
               echo "Study";
               break;
            
            case "Tue":
               echo "Study";
               break;
            
            case "Wed":
               echo "Study";
               break;
            
            
            default:
               echo "Relax on weekend.";
         }
      ?>
Study
-----------
for loop (specified number of time)
while (as long as condition is true)
do....while
foreach (loops for each element)
-----------

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