Question

How to generate an N-digit integer random number in PHP

Answer 1

function generate_n_digit_number(int $n): int {
    if ($n < 1) {
        throw new InvalidArgumentException("Error: n must be a positive integer (>= 1).");
    }

    // For n=1, range is 0–9; for n>1, ensure no leading zeros
    $lower_bound = ($n > 1) ? (int)pow(10, $n - 1) : 0;
    $upper_bound = (int)pow(10, $n) - 1;

    // Use random_int for secure, uniform distribution
    return random_int($lower_bound, $upper_bound);
}

echo generate_n_digit_number(1) . PHP_EOL;
echo generate_n_digit_number(4) . PHP_EOL;
echo generate_n_digit_number(10) . PHP_EOL;




/*
run:

3
8758
9913686272

*/

 

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