How to use the rand function to make numbers in a specific range?

Question

I would like to make random numbers in a specific range, like \"pick a random number between 18 and 35\"? How can I do that with the rand() function?

Answer 1

1. Do you want integers-only?
2. Do you want a uniform distribution?
3. Do you want to include both 18 and 35 as possible values?
4. What language would you prefer to use?

in general, if rand() returns a float value in [0.0 ... 1.0) (that is, you may get values arbitrarily close to 1.0 but not actually 1) then you will want something like

hi = 36
lo = 18
res = int( (hi-lo)*rand() + lo ) # returns random values in 18..35

Note that this will never actually return the hi value - therefore I have incremented it by 1 (ie, you will get all values from 18 to 35 inclusive, but never 36).

Hope that helps.