PHP Integers

• An integer is a whole number. That is to say, it is a number with no fractional component. For those who are familiar with C, a PHP integer is the same as the long data type in C. It is a number between -2,147,483,648 and +2,147,483,647.
• decimal: a base ten numbering system.
• Integers can be written in decimal, octal, or hexadecimal. Decimal numbers are a string of digits with no leading zeros. Any integer may begin with a plus sign ( + ) or a minus sign ( - ) to indicate whether it is a positive or negative number. If there is no sign, then positive is assumed.
  
  
  Valid decimal integers:

  1

  
  

  123

  
  

  +7

  
  

  -1007395

  
  
  Valid octal integers:

  01

  
  

  0123

  
  

  +07

  
  

  -01007345

  
  
  Valid hexadecimal integers:

  0x1

  
  

  0xff

  
  

  0x1a3

  
  

  +0x7

  -0x1ab7345

  
  
  Example : The PHP var_dump() function returns the data type and value of variables:
  
  
  <?php
  $a = 5;
  var_dump($x);
  echo "<br>";
  $x = -5;                                   // negative number
  var_dump($x);
  echo "<br>";
  $x = 0x8C;                            // hexadecimal number
  var_dump($x);
  echo "<br>";
  $x = 047;                              // octal number
  var_dump($x);
  ?>