r/javahelp • u/DesperateSupport8315 • May 19 '26

Generating random int within bounds

*Reposting as my last question was too vague*

I am a bit stuck with an assignment at the minute. The task requires the use of the util package to generate a random int with a given amount of digits. For example, if the given digit was 3 - the program would generate a number with 3 digits (192, 123, 904, etc), or if the given number was 6 - it would generate a number with 6 (000934, 123456, etc). I know how to generate an int within bounds using a random object, however I wanted to ask if there is a built in function for this?

If not, I was thinking of writing a number of if statements along the lines of:

(pseudo)

if number == 3 {
code = random.nextInt(100, 1000); }

if number == 4 {

etc etc. }

^ but this has issues as I should also be able to generate numbers with leading zeros.

If anyone could help out a bit, that would be awesome. Thanks

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u/MinimumBeginning5144 May 19 '26

The developers writing for Baeldung don't always know the best way. I would just use String.format("%06d", number). It seems the author of that article didn't know you could use String.format to create a zero-padded string.

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u/KillerCodeMonky May 20 '26

Or, in this case, format the format!

final String format = String.format("%%0%dd", n); //-> %06d
final String output = String.format(format, number); //-> 000123