PHP Math Exercises: Get random float numbers

Last update on June 02 2025 13:00:28 (UTC/GMT +8 hours)

10. Generate Random Float Numbers

Write a PHP function to get random float numbers.

Pictorial Presentation:

Sample Solution:

PHP Code:

<?php
function rand_float($st_num = 0, $end_num = 1, $mul = 1000000)
{
    // Check if the start number is greater than the end number
    if ($st_num > $end_num) {
        return false; // Return false if start number is greater than end number
    }
    // Generate a random integer between the multiplied start and end numbers,
    // then divide it by the multiplication factor to get a random float value
    return mt_rand($st_num * $mul, $end_num * $mul) / $mul;
}

// Test the rand_float function with different arguments and print the results
echo rand_float() . "\n"; // Random float between 0 and 1
echo rand_float(0.6) . "\n"; // Random float between 0.6 and 1
echo rand_float(0.5, 0.6) . "\n"; // Random float between 0.5 and 0.6
echo rand_float(0, 20) . "\n"; // Random float between 0 and 20
echo rand_float(0, 3, 2) . "\n"; // Random float between 0 and 3  
echo rand_float(0, 2, 20) . "\n"; // Random float between 0 and 2
?>

Output:

0.613314                                                    
0.886207                                                    
0.57955                                                     
17.570268                                                   
1.5                                                         
1.6

Explanation:

In the exercise above,

• function rand_float($st_num = 0, $end_num = 1, $mul = 1000000) {: This line defines a function named "rand_float()" with three parameters: '$st_num', '$end_num', and '$mul'. Default values are provided for these parameters.
• if ($st_num > $end_num) { return false; }: This line checks if the start number is greater than the end number. If it is, the function returns 'false'.
• return mt_rand($st_num $mul, $end_num $mul) / $mul;: This line generates a random integer between the multiplied start and end numbers (multiplied by the factor '$mul'), then divides it by the multiplication factor to get a random float value. This ensures the float value falls within the specified range.
• The subsequent "echo" statements test the "rand_float()" function with different arguments and print the results.

Flowchart :

For more Practice: Solve these Related Problems:

• Write a PHP function to generate a random float between two given numbers without using the rand() function.
• Write a PHP script to simulate random float generation using microtime() for increased precision.
• Write a PHP program to generate an array of random floating-point numbers within a specified range and print the results.
• Write a PHP function to generate a random float with a given number of decimal places by manipulating string representations.

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