Random generator (with weight)

Question

Hey all..
I want to make a random generator, which will pick a random object from a vector.
Each object in the vector has been assigned a weighted INT value between 1 -> 100.
I want the generator to distribute the generated choices: to pick more values that have been set with a higher weight priority.
For every 10 choices I want 3 of them to have a weight above 70.
6 of them to have a weight between 40 -> 69
1 of them to be below 40.
Any advice or guidance would be greatly appreciated�
Cheers,
Gav.

Answer 1

Anyway, if you want what you said, I would have three
vectors rather than one. They would contain the items
with weight 70 and above, the items with weight 40 to
69, and the items with weight below 40. I would keep
track of how many requests had been made, and if that
number % 10 was 0, 1, or 2 I would choose from the
70-and-up vector, if it was 9 I would choose from the
below-40 vector, otherwise from the middle-weight
vector. The resulting sequence violates several common
randomness rules, I'm sure, but it does satisfy the
requirements.The forces the order to be that of 70+, 70+, 70+, mid, mid, mid, mid, mid, mid, 40-
That's not really random?
What I'd do is this:
Create a "class" list upon initialization (and after every 10 requests) that is a shuffled list of "classes." (Your classes being 70+, mid, and 40-). This list will contain the 10 requests and be randomly shuffled.
Then remove an item from that list first per random request and go and randomly choose a number in that "class".
When the "class" list is empty (after 10 requests) you'll go back to the top and re-create and shuffle it again for the next 10.
That should work and guarentee a better randomness. The only thing you have left to consider is how to pick a random number of said class. This shouldn't be too hard, I'd recommend storing each class in a separate bin and randomly choose from that bin.