Creating Random Numbers
The last function you’ll learn about in this chapter is rand(), a random-number generator. All it does is output a random number:
$n = rand(); // 31 $n = rand(); // 87
The rand() function can also take minimum and maximum parameters, if you prefer to limit the generated number to a specific range:
$n = rand (0, 10);
These values are inclusive, so in this case 0 and 10 are feasible returned values.
As an example of generating random numbers, let’s create a simple “Lucky Numbers” script.
To generate random numbers:
- Begin a new document in your text editor or IDE, to be named random.php (Script 4.6):
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <title>Lucky Numbers</title> </head> <body>
Script 4.6. The rand() function generates a random number.
1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> 6 <title>Lucky Numbers</title> 7 </head> 8 <body> 9 <?php // Script 4.6 - random.php 10 /* This script generates 3 random numbers. */ 11 12 // Address error handling, if you want. 13 14 // Create three random numbers:
15 $n1 = rand (1, 99);
16 $n2 = rand (1, 99);
17 $n3 = rand (1, 99);
18 19 // Print out the numbers: 20 print "<p>Your lucky numbers are:<br /> 21 $n1<br /> 22 $n2<br /> 23 $n3</p>"; 24 25 ?> 26 </body> 27 </html> - Include the PHP tags and address error management, if you need to:
<?php // Script 4.6 - random.php
- Create three random numbers:
$n1 = rand (1, 99); $n2 = rand (1, 99); $n3 = rand (1, 99);
This script prints out a person’s lucky numbers, like those found on the back of a fortune cookie. These numbers are generated by calling the rand() function three separate times and assigning each result to a different variable.
- Print out the numbers:
print "<p>Your lucky numbers are:<br /> $n1<br /> $n2<br /> $n3</p>";
The print statement is fairly simple. The numbers are printed, each on its own line, by using the HTML break tag.
- Close the PHP code and the HTML page:
?> </body> </html>
- Save the file as random.php, place it in the proper directory for your PHP-enabled server, and test it in your Web browser . Refresh the page to see different numbers .