PHP Math Exercises: Generate random 11 characters string of letters and numbers

Last update on June 02 2025 13:00:26 (UTC/GMT +8 hours)

3. Generate Random 11-Character String

Write a PHP script to generate random 11 characters string of letters and numbers.

Visual Presentation:

Sample Solution:

PHP Code:

<?php
$x = rand(10e12, 10e16); // Generate a random number between 10^12 and 10^16
echo base_convert($x, 10, 36)."\n"; // Convert the random number to base-36 and echo it
?>

Output:

3b6jfwh18v2

Explanation:

In the exercise above,

• $x = rand(10e12, 10e16);: This line generates a random number between 10^12 and 10^16 using the "rand()" function. The range of the random number is specified using scientific notation, where '10e12' represents 10^12 and '10e16' represents 10^16.
• echo base_convert($x, 10, 36)."\n";: This line converts the generated random number '$x' from base-10 (decimal) to base-36 using the "base_convert()" function. Base-36 uses the digits 0-9 and letters A-Z to represent numbers. The converted number is then echoed to the output, followed by a newline character ("\n").

Flowchart:

For more Practice: Solve these Related Problems:

• Write a PHP function that generates an 11-character random alphanumeric string using shuffle() and substr(), ensuring no use of rand().
• Write a PHP script to generate multiple random strings of 11 characters and verify that each string contains at least one letter and one number.
• Write a PHP program to create a random 11-character string and then check its uniqueness across successive script executions.
• Write a PHP script to generate an 11-character string from a custom character pool and validate that it meets a predetermined entropy threshold.

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